The hydrostatic shock theory?


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Pyro
September 5, 2011, 06:16 PM
Sorry if I am beating a dead horse.
I've heard some people take is seriously and other dispute it as nothing more than a myth.
The newest addition I've heard to the subject is the pressure from the projectiles actually disrupting the valves that control heart function.
What's your take on this?

I tested some Magsafe SWAT loads in 38 Special last week and they pretty much bellyflopped. Very large cavities, very little fragmentation, very little penetration (and I thought Glaser Safety Slugs were bad). But the remaining phone book sections it did not penetrate had a noticeable ringed dent from the shock.
I wouldn't carry these, but it sparked my interest since this is one of the few rounds designed to just dump all of it's energy as fast as possible (faster than Glaser).

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KodiakBeer
September 5, 2011, 06:27 PM
I don't think it's completely a myth at least with rifles, but at handgun velocities it's a waste of time and effort.

What is a myth is the "dumping all its energy" mantra. When you shoot a handgun, how much energy is dumped in your palm? A similar amount of energy is dumped into the target (physics) and it isn't enough to make any difference. What counts is tissue destroyed along the path of the projectile, and that is not as simple as measuring kinetic energy.

gofastman
September 5, 2011, 06:35 PM
What's your take on this?
we (people) just dont know enough about it to give a diffinitive answer.

I think there is something to it, I would venture to guess that a FN 5.7
is more effective than a CCI SGB, even though id guess they penetrate about the same and leave a similar permanent cavity.
this is just me talking out of my rear end, its not based on science.

Strykervet
September 5, 2011, 06:39 PM
I don't think it's completely a myth at least with rifles, but at handgun velocities it's a waste of time and effort.

What is a myth is the "dumping all its energy" mantra. When you shoot a handgun, how much energy is dumped in your palm? A similar amount of energy is dumped into the target (physics) and it isn't enough to make any difference. What counts is tissue destroyed along the path of the projectile, and that is not as simple as measuring kinetic energy.
If it doesn't penetrate the target completely, then the round dumped all of its energy. That is the physics fact for the day.

If you can get something going fast enough, even air, it will kill. Bombs kill via shockwave as an example. That is 100% pure hydrostatic shock since there is no other way for the wave to hurt you. Also, if you are in a swimming pool (or water) when explosives go off, you'll feel it much more than if not. It doesn't take much to kill in water.

The FBI Miami shootout. One of the cops got hit in the neck with a 5.56. It passed through, didn't hit anything major, but it dropped him and he spent the rest of the gunfight paralyzed. Apparently the shock wave separated his spinal column causing it to pinch a nerve. Very lucky.

I've seen ballistics gel tests, and if they are similar to soft tissue, I can say that having my stomach shoved into my chest looks pretty uncomfortable to me, even if it is temporary. I've had bad gas before, it was temporary too, but I almost ended up in the ER.

Too many variables to say for certain how damage occurs and what does what, but I can say that it is very plausible.

gofastman
September 5, 2011, 06:44 PM
hydrostatic and shock are dichotomous
a shockwave can not be static

Pyro
September 5, 2011, 06:53 PM
hydrostatic and shock are dichotomous
a shockwave can not be static
Ok, hydraulic shock.

When you shoot a handgun, how much energy is dumped in your palm?
I'm pretty sure that 400 or more foot pounds isn't being dumped into my palm when I discharge a cartridge.

PolymathPioneer
September 5, 2011, 06:57 PM
I don't think it's completely a myth at least with rifles, but at handgun velocities it's a waste of time and effort.

I'm with Kodiak on this. Unless its a high powered rifle a pistol isn't in the same league here. I realize this is a little off the OP but as I have gotten older my focus has changed to bolt rifles (for North American and African game) and for home defense an 870 tricked out for night operation (reliability options, recoil reduction, tack light, high end eotech and infrared laser). I still have several excellent pistols (for carry in places we might visit far from home) but they are not the goto anymore, i.e. they are the backup if SHTF. I wonder if this is an age related phenomena. :rolleyes:

aggieoutlaw
September 5, 2011, 06:59 PM
I don't think the terminology implies that the shockwave is static. Hydrostatic just means that a fluid or medium is at rest/equilibrium.

I don't know a thing about this topic. But a shockwave is by definition a pressure front that moves faster than the speed of sound in a medium. Since the speed of sound is much faster in water than in air, I don't see how a subsonic (or even barely supersonic) projectile can cause a shockwave in a solid/liquid.

Cheers.

SlamFire1
September 5, 2011, 07:09 PM
A 22LR puts Squirrels down more reliably than a .177 airgun. The caliber is close, both put a hole all the way through the darn tree rats, and yet the LR is more positive in action.

Maybe there is something to it.

Squirrels are the Spawn of Satan!!


http://img.photobucket.com/albums/v479/SlamFire/Squirrelevial.jpg

Friendly, Don't Fire!
September 5, 2011, 07:18 PM
If the projectile causes instant pressure increases of blood and other bodily fluids, anything connected and surrounding those fluids would most likely be affected in one way or another, i.e., a hit to the heart or main artery could cause a pressure-burst of a vessel or artery in the brain (just one example).

I shot a huge groundhog once that was lying there on a golf course (no golfers were around, and I had permission from the owner to take him out), he was facing me and he was about 25 pounds or more in weight, based on his extremely large and fat size. I had a .270 with 130g Hornady Spires going in excess of 3,200 FPS. I laid down with the sling around my left arm and was approximately twenty to thirty paces from him.

The bullet went lengthwise inside the animal and did not escape, nor did it rip open anything visible on the exterior. However, the way the woodchuck went airborn and twisted as it flew about 10' was enough to convince me that, had I opened him up, I doubt very much there would have been anything recognizable left to see in whole! The energy of both the speed and extremely high rotational force (centrifugal) of the projectile was clearly visible the way he flung around during the short ten-foot, or so, flight.

The energy was completely and thoroughly expelled within the animal - his being flung in such a way was the visual manifestation of both the projectile's forward energy and twisting (rotational) energy! When I picked him up, he was just like a blob of jello, very little bone structure keeping him in any particular position.

PolymathPioneer
September 5, 2011, 07:19 PM
A 22LR puts Squirrels down more reliably than a .177 airgun. The caliber is close, both put a hole all the way through the darn tree rats, and yet the LR is more positive in action.

Maybe there is something to it.

Squirrels are the Spawn of Satan!!


http://img.photobucket.com/albums/v479/SlamFire/Squirrelevial.jpg
Slamfire, please don't tell me those are Bama squirrels. I used to say a cape buff is no more dangerous than a ground squirrel at 100 yards. However, that could very well change my perspective LOL. :D

Derek Zeanah
September 5, 2011, 07:22 PM
My wife worked on quite a few gunshot wounds in medical school, and she states with no equivocation that there was usually damage beyond the tissue that was in the path of the bullet. You know, "from shockwaves."

Just an anecdote.

BCRider
September 6, 2011, 12:59 AM
A 22LR puts Squirrels down more reliably than a .177 airgun. The caliber is close, both put a hole all the way through the darn tree rats, and yet the LR is more positive in action.


And then there's the hunting videos of squirrels and gophers hit with the .17HMR or .22WMR rounds where the exit wound slide looks like it had a small stick of explosive go off inside the animal. So it seems like velocity is the key. All three of the rounds .177 air pellet, .22LR and .17HMR, may go right through but the .17 seems to set up a shock wave ahead of it that splits things open a lot more than the slower options.

Prosser
September 6, 2011, 03:25 AM
There are handgun calibers that rival rifles for energy, and, they kill far beyond their fps of energy, with no real explanation.
Once you get past .460 caliber, strange stuff starts happening, and, those big bullets start moving REALLY fast, thanks to those BIG cases.

There is one load in particular that I promise you develops hydrostatic shock out of a handgun: Hornady's factory 200 grain .460 at 2300 fps.

I might suggest that as the caliber increases, the velocity required for hydrostatic shock is reduced.

I will say that the absolute most effective rounds I've ever used on a water jug weren't particularly fast, just 2300 and 2150 fps. Strange, but when a 500 grain bullet, 458 hits at 2300 fps:
http://i45.photobucket.com/albums/f99/Socrates28/VanHornLott450n2/GS458LOTT-1.jpg

That said, for some reason, the 600 grain barnes .510 caliber solid at 2150 fps
well, look at the way the jug disappears:
http://i45.photobucket.com/albums/f99/Socrates28/VanHornLott450n2/GS510VANHORNWEB.jpg
This wasn't picture timing. the 600 grain bullet displaced so much water, so much faster that the jug exploded out the sides, rather then being forced through the cap, as happens with most jugs.
For example, this is a .450 Nitro Express, 500 grains, 2150 fps, and notice how the water goes UP. The .510 Van Horn hits so hard, it doesn't have time to do this:
http://i45.photobucket.com/albums/f99/Socrates28/Jack%20and%20the%20jug/Jackandthejugtheshot450nitro.jpg
[URL=http://s45.photobucket.com/albums/f99/Socrates28/Jack%20and%20the%20jug/?action=view&current=Jackandjug2.jpg]http://i45.photobucket.com/albums/f99/Socrates28/Jack%20and%20the%20jug/th_Jackandjug2.jpg
http://i45.photobucket.com/albums/f99/Socrates28/Jack%20and%20the%20jug/Jackandjug3.jpg

KodiakBeer
September 6, 2011, 04:34 AM
I'm pretty sure that 400 or more foot pounds isn't being dumped into my palm when I discharge a cartridge.

You'd be wrong. As per Isaac Newton: For every action, there is an equal and opposite reaction.

There is of course a hydraulic displacement of soft tissue and fluids when a bullet strikes. You can test that by gently dropping a marble into a bucket of water, then throwing the same marble into a bucket of water. The larger splash from the thrown marble is your proof that the displacement occurs and that velocity increases the violence of that displacement.

I just don't think that typical handgun velocities are enough to disrupt heart valves (as per the question in the OP) or create a neurological shock due to a sudden increase in vascular pressure that some people claim.

A rifle? Maybe. A standard defense handgun? Not.

Friendly, Don't Fire!
September 6, 2011, 05:22 AM
I filled a perfectly good, almost new, 30 gallon Rubbermaid plastic trash can with water and shot into the upper part, where the water column was "thickest."

The water flew everywhere (I was drenched) and the trash can completely tore from top to bottom on the front - where the bullet entered. I found the 500 Magnum 275g Barnes Solid Copper X bullet (XPB) on the far side, measuring 30 inches of water it went through, then it stuck into the plastic on the far side by one of the razor-sharp petals that had opened perfectly along with the other three petals!

I couldn't believe what I saw! In fact, I was angry at myself for ruining a perfectly-good trash can!

I was convinced, that load would drop anything around my neck of the woods!

Prosser
September 6, 2011, 06:30 AM
Likewise the 275 grain .475 Linebaugh version:
Something about having a quarter sized hole punched through you at 1560 fps, and, that's a minimum pressure load:

http://i45.photobucket.com/albums/f99/Socrates28/quartersand275grainbullet.jpg

That size hole is the same a 2 bore rifle makes, but without the 3500 grain bullet...

mrmeangenes
September 6, 2011, 08:23 AM
"hydrostatic and shock are dichotomous"

I seed a Dichotomous t' other day : 'T'was 'bout like one of them Alabama squirrels- so I turned the hose on (for hydro power) an' shocked it purt bad.

"T'was downright anamorphic when I finished.

brickeyee
September 6, 2011, 11:47 AM
"When you shoot a handgun, how much energy is dumped in your palm? A similar amount of energy is dumped into the target (physics) and it isn't enough to make any difference."

Major physics fail here.

Momentum is conserved, NOT energy.

Recoil is a momentum effect, equal and opposite.

You'd be wrong. As per Isaac Newton: For every action, there is an equal and opposite reaction.

WRONG.

Momentum, NOT energy.

Momentum is mass * velocity.

Energy is 1/2 * mass * velocity^2.

Maybe you should actually read Newton.

Shawn Dodson
September 6, 2011, 12:37 PM
The newest addition I've heard to the subject is the pressure from the projectiles actually disrupting the valves that control heart function.
What's your take on this?

CPR doesn't damage heart valves.

I tested some Magsafe SWAT loads in 38 Special last week and they pretty much bellyflopped. Very large cavities, very little fragmentation, very little penetration (and I thought Glaser Safety Slugs were bad). But the remaining phone book sections it did not penetrate had a noticeable ringed dent from the shock.
I wouldn't carry these, but it sparked my interest since this is one of the few rounds designed to just dump all of it's energy as fast as possible (faster than Glaser).

There are several documented cases of police officers who were shot in the torso by shotgun slugs that were stopped by soft body armor. I’m unaware of any that were physiologically incapacitated by the rapid transfer of energy through the armor and absorbed by the body (the "dent").

Bombs kill via shockwave as an example. That is 100% pure hydrostatic shock since there is no other way for the wave to hurt you.

The shockwave created in air by an explosive is a true shock wave, i.e., the air is compressed. When the compression (shock) wave strikes the body it produces blunt trauma.

Also, if you are in a swimming pool (or water) when explosives go off, you'll feel it much more than if not. It doesn't take much to kill in water.

Water, because it is a fluid, does not compress. The wave created by an explosion in water is not a compression wave, it is a pressure wave. When the pressure wave strikes the body it produces blunt trauma.

The FBI Miami shootout. One of the cops got hit in the neck with a 5.56. It passed through, didn't hit anything major, but it dropped him and he spent the rest of the gunfight paralyzed. Apparently the shock wave separated his spinal column causing it to pinch a nerve.

The bullet, fired by Michael Platt, struck a vertebra in Gordon McNeill’s neck. The impact was transmitted mechanically from the bullet to the vertebra directly to the spinal cord, producing a blunt trauma concussion of the spinal cord which temporarily interrupted nerve transmission.

And then there's the hunting videos of squirrels and gophers hit with the .17HMR or .22WMR rounds where the exit wound slide looks like it had a small stick of explosive go off inside the animal. So it seems like velocity is the key.

The bullet simply produced a temporary cavity that exceeded the size of the animal’s body. The tissues ripped apart because they were unable to tolerate the scale of the stretching.

A larger caliber low velocity bullet that produces a similar sized temporary cavity will produce the same explosive-like affect in a small animal.

easyg
September 6, 2011, 12:45 PM
Momentum is conserved, NOT energy.

Recoil is a momentum effect, equal and opposite.
But isn't it energy that causes the momentum of the slide?

And how would one's hand feel if the movement of the slide and the recoil spring didn't reduce the felt recoil?

And would there be any damage if one's arm and hand and wrist were all fixed in a manner where they could not flex or be moved during recoil?

Loosedhorse
September 6, 2011, 01:03 PM
Try this: have someone (Average Joe, not a boxer) punch you on the palm as hard as he can (you are allowed to let the palm move with the punch, "in recoil.")

Then have him punch you as hard as he can in your solar plexus, while you are standing with your back against a wall.

Same punch, same energy, different results. When you shoot a gun, your palm does not absorb all the energy--the energy gets distributed elsewhere in the body by your muscles and bones. In fact, your muscles and bones act as a brake on the gun from the moment it is fired. By contrast, the bullet hits flesh at a speed that does not allow the flesh "to roll with the punch."

Any shotgunner knows the consequences of not mounting the gun properly, so that it is allowed some free travel before your shoulder and cheek begin to decelerate it. Hopefully, few shotgunners know what happens if you fire with your shoulder planted firmly between the stock's butt and a tree trunk.

Oh, has everyone looked at this? http://en.wikipedia.org/wiki/Hydrostatic_shock Pretty fair summary, I think.Water, because it is a fluid, does not compress.Actually, water does compress. The same amount of pressure, however, compresses water far less than it compresses air (that's the main reason that sound travels more quickly and farther in water than in air.)

SN13
September 6, 2011, 01:23 PM
Proper Shot placement makes all these arguments moot anyway.

Loosedhorse
September 6, 2011, 01:43 PM
The newest addition I've heard to the subject is the pressure from the projectiles actually disrupting the valves that control heart function.
What's your take on this? CPR doesn't damage heart valves.A fluid shock wave would in theory damage heart valves by producing an intravascular pressure that momentarily exceeds the valves' mechanical limit. This scenario is quite distinct from CPR, where external (extravascular) pressure is being added to to a low-or-no-pressure intravascular system.

That said, I know of no case report of remote cardiac valve injury from gunshot wound.

"The Courtneys" are largely responsible for the recent, fresh looks at this theory:

http://www.scribd.com/doc/19483327/The-Ballistic-Pressure-Wave-Theory-of-Handgun-Bullet-Incapacitation
http://www.google.com/url?sa=t&source=web&cd=20&ved=0CFAQFjAJOAo&url=http%3A%2F%2Farxiv.org%2Fpdf%2Fphysics%2F0701268&rct=j&q=bullet%20temporary%20cavity%20torn%20aorta&ei=Tjk8ToWnOpDVgAfSmqzPBg&usg=AFQjCNHv8WdWCz8v4QShgIgLIuWzXLt2uA

brickeyee
September 6, 2011, 02:39 PM
But isn't it energy that causes the momentum of the slide?

The energy that was used to drive the bullet.

Energy is NOT the same as momentum.

You can calculate the momentum of a recoiling handgun, and then since you know the mass of the gun and the velocity it is recoiling at, compute a recoil energy.

This is refereed to as the 'free recoil energy.'

It is WAY less than the energy the bullet has.

Energy cannot be created or destroyed, just have its state altered, but it is not conserved in the manner you are thinking.

Newton was not talking about energy, he was talking about force.

Pyro
September 6, 2011, 04:06 PM
Seems that much of that energy is transferred into the stretch/permanent cavity as seen in this image from BrassFetcher.
http://img20.imageshack.us/img20/8182/unled2wp.jpg (http://imageshack.us/photo/my-images/20/unled2wp.jpg/)
Every fragmenting round I have tested always have quite large cavities before total fragmentation compared to JHP or other rounds.

Boy I should have listened more in physics class.

KodiakBeer
September 6, 2011, 04:08 PM
Any shotgunner knows the consequences of not mounting the gun properly, so that it is allowed some free travel before your shoulder and cheek begin to decelerate it.

True enough, but does that destroy your shoulder? You can also find threads here about various rifle calibers and their "punishing recoil". The Mosin Nagant is the classic example where one person shoots it hunkered down on a bench, while another stands on his hind legs allowing his upper body to flex. The "hunkerer" says the rifle has savage recoil, the "stander" says it shoots like a pussy cat.
It's the same with a handgun, while it's true the flex of your wrist and arm slow down and "brake" the recoil, you can also shoot that handgun off a bench with your arms braced and feel far more recoil. Still, there isn't enough to damage anything.

The bigger point isn't arguable really, since so many people hunt with handguns. I've shot deer with .44 mag, .45 Colt and .45 acp. It kills them but it isn't the same dramatic kill you often get from a high velocity rifle. And when you dress a handgun killed deer, you don't get the same "lung soup" you often find in a rifle killed deer.

Really, while gelatin and mathematical formulas are all well and good, the question should really be addressed in the hunting forum. Over there you'll get 1st person accounts of both the kills and observations of what the organs of the animal looked like when dressed.

Prosser
September 6, 2011, 04:22 PM
Try this:
Go to a recoil calculator, and put in a 7000 grain, that's a one bore, one pound bullet, at 1000 fps. Enter the gun weight as 7000 grains, or one pound. Recoil Energy of 16,474 foot pounds, and Recoil Velocity of 1,030 fps. You'll notice that if you put in a one pound gun, you get a recoil velocity nearly identical to the velocity of the projectile.

The ft-lbs of energy also is very close to the recoil energy above:
Energy of 15,547 foot-pounds for a 7000 grain bullet at 1000 fps. The variance I think, is due to the large powder amount I put in for the above load.

So yes, equal and opposite reaction does appear to be the case.

Gunweight REALLY slows down recoil when using bullets that are lighter then the gun. Going up a pound on a handgun usually cuts the recoil in half.

As far as letting a heavy recoiling rifle get a running start on your shoulder: We do the reverse. We pull the gun hard into our shoulder with one arm, so it doesn't get a chance to
hit us at it's recoil velocity. That .510 Van Horn recoils at Recoil Energy of 98 foot pounds, and Recoil Velocity of 26 fps. I'm making it look like I can take that much, but, without a PAST recoil
pad spreading the impact, I've got a real good chance of having my shoulder separate from that energy. That's like getting hit by a heavyweight boxer, just not as fast.

At a certain point, and gun design, that which works with lower calibers no longer works. I have a Ruger Maximum with Bisley grips. The Bisley grip was originally designed for
light recoiling target guns, to take the recoil straight back. Some have found it allows the gun to roll with the shot. I have not. When shooting maximum loads, 525's at 1350 fps,
it feels like the tissue in my right palm has been hit with a baseball at high velocity. Feels like the tissue is actually strained and separated. This recoil level is:
Recoil Energy of 53 foot pounds, and Recoil Velocity of 31 fps.
At this point you have the gun moving so hard it doesn't get a chance to roll up, and drives straight back into your arm. It's not fun.

Kodiakbeer:
If you take your shotgun load, say 525 grains at 1350 fps, and use a .5 pound shotgun, the recoil would be Recoil Energy of 381 foot pounds, and Recoil Velocity of 221 fps. I would suspect
this would destroy your shoulder.

Eb1
September 6, 2011, 04:42 PM
I don't think anyone on this thread has answered the question. Nor do they have a scientific answer that provides a true backup to their answer.

In real world experience for me. A Hogue mono grip makes the recoil from my 5.5" 44 Magnum way less than with the cowboy grips.
A .223 55 grain SP out of a 20" barrel AR-15 will blood shot meat like nothing I have ever shot a deer with inside of 50 yards.
A .25-06 will most likely drop a deer. Where a 30-30 will not with an equal located hit. These are my real world experiences, and I can't tell you why. I just know that it is.

I have seen a .22-250 totally destroy ever vital organ in a deer @ 200 yards with a 55 grain SP. I have see a CT BT totally destroy ever organ on a quartering shot on a deer @ 300 yards. I have seen a 170 grain 30-30 round nose plow through a deer @ 50 yards, and it run for 150 yards more than once. I have see a 125 grain HPFN from 30-30 drop deer with the same shot placement as the 170 grain RN. I don't know why. It just is from point of view.

I believe that speed with the right projectile is a better killer. This is until you get into .45 calibers with weight of 200+ grains. Then the slow and big argument comes into play.
Either way. Fast and small or Big and slow are the key. Medium speed with Medium size bullets to me are a toss up of DRT kills, and I am learning to stay away from the med./med. rifles for hunting. Yes, they kill, but the chase may be on with a good shot placement where a .243, .25-06, 6mm, etc will most likely give you the results you want over the medium calibers with mediocre velocities.

KodiakBeer
September 6, 2011, 05:12 PM
Kodiakbeer:
If you take your shotgun load, say 525 grains at 1350 fps, and use a .5 pound shotgun, the recoil would be Recoil Energy of 381 foot pounds, and Recoil Velocity of 221 fps. I would suspect
this would destroy your shoulder.

I don't think so, though no doubt you wouldn't want to repeat the experiment. However, concentrate that force into a buttstock .68 caliber in size and you'd certainly sustain some permanent damage.
But really, it is that dispersion of force that is the heart of the matter here. When you shoot a firearm, the recoil force is dissipated by a number of factors, all mentioned in earlier posts.
At the other end when the projectile strikes, similar factors come into play since we are talking about the secondary damage around the actual projectile. That force is also being dissipated (absorbed) by the cone of tissue and fluid around the actual projectile.

Again, I'll point to handgun hunters. My experience with that is (relatively) limited, but the prevailing wisdom is usually "you can eat right up to the hole". For example, a deer hit through the liver with a rifle means no liver and onions for you. A deer hit through the liver with a handgun means a liver with a hole through it.

Loosedhorse
September 6, 2011, 05:45 PM
But really, it is that dispersion of force that is the heart of the matter here.It's a big part of it, but...

When a gun fires, the ratio of kinetic energy of the bullet to kinetic energy of the rifle is the same as the ratio of the mass of the rifle to the mass of the bullet. To the extent that the rifle and shooter form a solid connection (that is, the rifle is not allowed to free-recoil), the effective mass of the rifle is made even greater, and even less energy is delivered to the rifle-shooter system.

That, coupled with the diffusion of impulse over the surface of the pistol grip or butt, plus the elastic properties of a butt pad/rubber grip and of the shooter's joints and flesh, result in a less destructive result at the butt end than at the muzzle end.

Prosser
September 6, 2011, 05:45 PM
I will say again:
There ARE handgun rounds, factory rounds, that equal rifle ballistics, and create Hydrostatic/dynamic shock. A 200 grain, .452" caliber bullet, at 2300 fps, in .460 S&W is a combination that is in the rifle category.

Also keep in mind that from game observations, there are combinations that flat out work, regardless of ballistics.

Something happens when a .475 LFN, 420 grains, hits a deer in the ham, and the bullet travels the length of the deer, hits nothing vital, and exits. Yet the deer drops dead on the spot.:what:

Likewise the guys that hunt with these things swear by heavy, LFN bullets, at 1350 fps, some even slower, like 525's at 1100 fps, and that they kill like the Thor's Hammer.

I think that the bullet meplat has a huge impact, if you'll excuse a pun, on impact with the target. The larger the meplat, the geometrically more energy
is put on target in the initial impact. This may create hydrodynamic shock. Also, I think that maintaining the velocity through the target, due to the extremely heavy bullets creates havock, using both temporary and permanent wound channels.

The other alternative is also there. With these huge cases we can out Lee Jurras' Lee Jurras, by loading 180-220 grain bullets at rifle velocities, and
create hydrodynamic shock.

So yes, you can create loads that create hydrostatic shock in a handgun.
It may have to be a LARGE handgun, but it is possible, and, some factory loads do it right now.

KodiakBeer
September 6, 2011, 05:58 PM
There ARE handgun rounds, factory rounds, that equal rifle ballistics, and create Hydrostatic/dynamic shock. A 200 grain, .452" caliber bullet, at 2300 fps, in .460 S&W is a combination that is in the rifle category.


Yeah, but we aren't talking about those. We are talking about common defense cartridges like the .38 special posed by the OP.

KodiakBeer
September 6, 2011, 06:11 PM
That, coupled with the diffusion of impulse over the surface of the pistol grip or butt, plus the elastic properties of a butt pad/rubber grip and of the shooter's joints and flesh, result in a less destructive result at the butt end than at the muzzle end.

I agree, but the question lies in how much secondary destruction occurs around the impact point. I've shot deer with a handgun and I've shot deer with a rifle. My own lyin' eyes tell me that there simply isn't much peripheral damage generated by the rather modest velocity of a handgun round. You open the chest and the organs are still intact, with holes in them.

With a rifle the destruction is often massive - far more than can be accounted for by contact with the slug. I don't know what velocity you begin to see significant amounts of peripheral damage, but it's well beyond the 1000 - 1200 fps you get in standard defensive handguns.

dcarch
September 6, 2011, 06:16 PM
@mrmeangenes: That's got to be just about the funniest thing I've read this week! :D

brickeyee
September 6, 2011, 08:15 PM
So yes, equal and opposite reaction does appear to be the case.

By making the gun weight and bullet wight identical you are going to have the same momentum since it MUST be conserved.

if the recoiling gun and the bullet both have the same velocity and mass, they are going to have the same energy.

When you have a gun weight that is many hundreds of times the bullet weight (an 8 pound rifle is over373 times the weight (and mass) of a 150 grain bullet) the recoil velocity of the gun is cut by hundreds of times.

Put the velocity into the kinetic energy equation (1/2 * m * v^2)
and the energy is a very small fraction of the bullet.

You feel nothing compared to the energy the bullet has.

Loosedhorse
September 6, 2011, 09:24 PM
There ARE handgun rounds, factory rounds, that equal rifle ballistics, and create Hydrostatic/dynamic shock.According to the Courtneys, any handgun round that produces 1000 psi of pressure wave in the chest is sufficient to cause hydrostatic shock. Fragmenting bullets produce greater pressure magnitude than non-fragmenting bullets. Bullets penetrating 10-12" produce more pressure than bullets penetrating 14" or more. For example, a bullet which does not fragment and penetrates 14" needs over 700 ft-lbs of energy to produce 1000 PSI. In contrast, a bullet which fragments and penetrates 12" needs just under 450 ft-lbs of energy to produce 1000 PSI.
As a reference, some 124gr 9mm+P loads will go 470 ft-lbs of muzzle energy; so can some 125gr .38+Ps. It is "an emerging theory," so add salt to taste.By making the gun weight and bullet wight identical you are going to have the same momentum since it MUST be conservedI remember a physics quiz question in high school that ran, "If the bullet is heavier than the gun..."

The answer: "Then the shooter is in more danger than the target." :D

MachIVshooter
September 6, 2011, 09:37 PM
I don't know what velocity you begin to see significant amounts of peripheral damage, but it's well beyond the 1000 - 1200 fps you get in standard defensive handguns.

It starts to occur around 2,000 FPS.

Handgun bullets at normal handgun velocities do produce hydraulic shock, which creates the temporary cavity. It's just not enough to exceed the elastic limits of most human body tissues, which is why bruising is usually the extent of peripheral damage from handgun bullets (the capillaries had their elastic limits exceeded, but the tissue did not).

I also have no doubt that hydraulic shock can disrupt organ and nervous system function without actually damaging the tissue, but then the disruption is temporary, usually momentary. A sneeze or cough also disrupts these functions, as does a bump on the noggin. There are miles of separation between "disrupting function" and "damaging tissue".

The comparison to shooting a rodent has already been addressed. Using such a small body to demonstrate the effectiveness of a bullet meant to dispatch much larger creatures is flawed for obvious reasons; A squirrel is a 0.5 to 2 lb animal, and shooting one with a .45 would be comparable to hitting a human with a 203mm artillery round. It's all about scale.

Ole Humpback
September 6, 2011, 10:51 PM
What is a myth is the "dumping all its energy" mantra. When you shoot a handgun, how much energy is dumped in your palm? A similar amount of energy is dumped into the target (physics) and it isn't enough to make any difference.

You'd be wrong. As per Isaac Newton: For every action, there is an equal and opposite reaction.

Kodiak, you're playing too strict with the laws of physics. You're treating the action of firing a gun as a static situation when its actually a dynamic situation.

First off, you need to understand that the bullet kinetic energy is not reacted into the gun, rather it is the force of rapid pressure change of the burning powder in the cartridge. When the primer is struck, it ignites the powder, which rapidly burns and changes into a gas. Using the combined gas law of PV=nrt to determine cartridge pressure, we can then set about figuring out the forces being translated into the frame of the gun and bullet.

Since pressure is defined as P=F/A, we look at the internal surface area of the cartridge and the surface area of the base of the bullet. Once these two are known, then we can determine forces acting on the cartridge and bullet. The forces inside the cartridge prior bullet release are symmetrical, equal amounts of force all around the cartridge. However, when the bullet is released the forces are asymmetrical, most of the force acts on the bullet and not on the gun.

As the bullet moves down the barrel, pressure is being reduced due to an increase in volume (as the bullet is displaced, gases take its place). The farther down the barrel the bullet goes, the less pressure there is acting on the gun. As the pressure is decreasing, the area for the pressure to act on is increasing which means the force is decreasing. Since both pressure & area are square units, pressure decreases by a square root for each unit increase in area (a 1 unit increase in area results in a 4 unit decrease in pressure, a 2 unit increase in area means a 16 unit decrease in pressure, ect.). The progression of pressure reduction is not linear, its exponential. This results in an exponential reduction of force the farther down the barrel the bullet goes.

Once the bullet leaves the barrel, all the remaining pressure exits the muzzle following the path of least resistance since the primer was struck. The path of least resistance in the case of firing a gun for the cartridge gases is to push the bullet out of the gun.

Now onto recoil. Recall how the pressure goes from symmetrical to asymmetrical once the bullet is released, this defines the recoil you feel. To define the symmetrical pressure recoil force, you need to add another variable: time. The symmetrical pressure recoil force is F=PAλ. λ is the time that is experienced at that specific PA. Since λ in the case of symmetrical cartridge pressure is defined in pico-seconds (millionths of a second), the max recoil force attainable is extremely low. This is called a specific impulse. The forces during a specific impulse can be tremendous, but short time frames drastically reduce the actual force of the impulse. Also, the cartridge base that pushes against the firearm itself is exponentially bigger than the base of the bullet, which leads to lower force imparted on the frame of the firearm than the base of the bullet during the specific impulse. Once the cartridge pressure becomes asymmetrical, the force acting against the gun drops exponentially.

Now, to sort out kinetic energy vs recoil. Kinetic energy is F=ma. In the case of a firearm, a is acceleration with a given direction: velocity. Convert grains to pounds and multiply by muzzle velocity to get ft/lbs of kinetic energy. As for recoil, the specific impulse that acted upon the cartridge base is greater than the weight of the gun. Subtract out the weight of the gun in pounds and you get the actual recoil force in pounds. Since the body isn't a rigid structure, your hand & arm displace to absorb the small amount of force involved.

A gun is nothing more than a pressure vessel that controls the direction and release of pressure.

As for hydraulic shock, apply the same math plus the average speed of sound in flesh to determine the rate at which the bullet kinetic energy will be imparted, determine the λ for bullet/tissue interaction time and you get a good idea of how much hydraulic shock will be imparted by any given round.

1stmarine
September 6, 2011, 11:01 PM
There are many studies about the subject. The most comprehensive one I found in the library of Cornell University. It describes quite in detail the effects of hydrostatic pressure in human targets. Try google it, you migh find it.

aggieoutlaw
September 6, 2011, 11:37 PM
Ole Humpback,

I follow you conceptually but have some confusion about your physics.

If we assume that the ideal gas law holds (which I am not sure is valid at the combustion temperature/pressure...but for the sake of argument), then shouldn't pressure decrease inversely with volume? Since the barrel is (for our intents and purposes) approximately a right circular cylinder, the volume is Base x Height (pi r^2 times bullet position in barrel as a function of time). Perhaps as a function of time, the graph of chamber pressure might appear to be decreasing somewhat 'exponentially'. I think that as a function of volume or bullet position, it would appear inversely linear (ignoring any gas or structural non-linearities). Thoughts?

When you say 'exponential', I believe you mean inversely proportional to a cubic or quartic. That is, x^-n is not the same as exp(-x). Your example was 2^-4 = 1/16. An exponential function grows (or shrinks) much faster than a polynomial. Again, you might be right about the exponential decay as a function of time, I just haven't given the equations much real thought.

Later you describe force as a pressure times an area times a time. I believe you mean an impulse (similar to momentum). I think you called it that as well. Is a 'symmetric pressure recoil force' another term for impulse or momentum? Also, I believe you mean microseconds which is only really fast, rather than picoseconds (10^-12 s), which is crazy fast.

When you describe kinetic energy, I believe you mean KE = 1/2 m v^2. This will actually produce substantially larger numerical quantities (in Imperial or SI units) than the mass times the velocity (which is momentum, a useful value for the discussion of recoil).

Anyway, this is a good discussion. I enjoyed your analysis about rigid structures in addition to the mass relationships between momentum transfer. You know you are having fun when you start discussing material non-linearities and structural dynamics on a gun forum!

I'm interested to hear your thoughts about my pressure vs time and pressure vs bullet position hypothesis.

Cheers!

brickeyee
September 7, 2011, 12:14 PM
Now onto recoil. Recall how the pressure goes from symmetrical to asymmetrical once the bullet is released

Recoil starts as soon as the bullet starts to move in the barrel.
F=ma and the bullet is accelerating.

KodiakBeer
September 7, 2011, 02:27 PM
A gun is nothing more than a pressure vessel that controls the direction and release of pressure.

Yeah, we've covered some of those bases, but when all is said and done the same energy is directed backwards as is driving the projectile forwards. That energy is spread out over a longer duration and the weight of the gun, the flex of your hands and/or body, etc, all serve to make that energy controllable.

One might compare it to shooting a bow. The reverse energy in that device is taken up as you retract the arrow and stored in the limbs of the bow. It's still there even if the "recoil" is prior to releasing the arrow.

KodiakBeer
September 7, 2011, 02:35 PM
It starts to occur around 2,000 FPS.

My "gut" tells me that's about right, though I don't think there's an objective way to test that. There are too many types of tissues and too many angles and variables in a gunshot wound to establish a "law".

I do know that at typical hunting rifle velocities (2600/3000 fps+), a pass-through rib shot on a deer or other critter of similar size will produce "lung soup". A handgun round even up to magnum velocities of something like 1400 fps, doesn't have that effect.

Prosser
September 7, 2011, 03:28 PM
2150 fps has been a bit of the Holy Grail for velocity for a long time.

I suggest we rethink the way we view 'magnum' handguns. The .475 Linebaugh will push a 275 grain bullet at 1560 fps, using a MINIMUM powder charge of AA 9. Max loads will run a 325 grain bullet at 1630 fps.

The .460 S&W will push 200 grain bullets over 2300 fps, and 200-260 grain bullets all over 2100 fps. That's a LOT of velocity from a handgun.

The 500 S&W will push a 275 grain bullet over 2100 fps. That's pretty much a rifle round.

KodiakBeer
September 7, 2011, 03:55 PM
Well, I don't think many will adopt a .460 or .475 for defense carry, against two-legged predators anyway...

snooperman
September 7, 2011, 04:02 PM
Hydrostatic shock is real and not a myth. It describes a penetrating bullet that can produce incapacitation in living things through the hydraulic effect in liquid tissues. Neural damage can occur from hydrostatic shock. A bullet wound to the chest can cause brain hemorrhaging from fatal hits to the chest from handgun bullets. Human autopsies results have prooved that this phenomenon is real and not a myth. The journal of Neurosurgery has published data that this scientific evidence is well established. ***See Wikipedia- Hydrostatic Shock for more.

Odd Job
September 7, 2011, 05:14 PM
Hydrostatic shock is real and not a myth. It describes a penetrating bullet that can produce incapacitation in living things through the hydraulic effect in liquid tissues. Neural damage can occur from hydrostatic shock. A bullet wound to the chest can cause brain hemorrhaging from fatal hits to the chest from handgun bullets. Human autopsies results have prooved that this phenomenon is real and not a myth. The journal of Neurosurgery has published data that this scientific evidence is well established. ***See Wikipedia- Hydrostatic Shock for more.

It's all real according to Michael Courtney, yes ;)

Loosedhorse
September 7, 2011, 05:41 PM
the same energy is directed backwards as is driving the projectile forwards.Not strictly true.

The bullet and the gun (if unrestrained and allowed to recoil freely) will have the same momentum in opposite directions as the bullet clears the muzzle. However, the bullet will have more energy (assuming it is lighter than the firearm).

The bullet's base and the breachface (or boltface) are of course exposed to the same pressure (accelerating force) for about the same time. But during that time the bullet travels more forward than the breachface does backward. And energy is force times distance.The reverse energy in that device is taken up as you retract the arrow and stored in the limbs of the bow. It's still there even if the "recoil" is prior to releasing the arrow.Actually, the potential energy stored in the drawn bow is analogous to the potential energy stored in the gunpowder.

There is no "recoil" before releasing the arrow. If the arrow were released from an unrestrained bow, the bow would move backward with the same momentrum with which the arrow moves forward.

RX-178
September 7, 2011, 05:53 PM
I've said it before, and I'll say it again, I think this whole debate is two different camps writing page-long physics articles to split hairs.

Let's take hydrostatic shock theory first. In order to generate the most possible hydrostatic pressure in the target, you want to put the shot into areas of the body that have the most fluids, organs, etc, center of mass. That way you get enough of a pressure wave to travel through the bloodstream, damage the brain, and incapacitate the target.

Now for the internal bleeding/organ failure theory. You want to put your shot in the areas of the body to do enough damage to the internal organs as possible, in order to cause bleeding severe and rapid enough that the target loses the ability to function and is thusly incapacitated.

So in short, if you believe in the hydrostatic shock theory, you aim center of mass.

And if you don't believe in the hydrostatic shock theory... you aim center of mass.

Now, you guys have demonstrated you can explain Newtonian Physics and such... can you now explain to me what the big difference is here?

Loosedhorse
September 7, 2011, 06:03 PM
can you now explain to me what the big difference is here?Sure. It centers on whether the only way to get incapacitation is to pucture vessels and destroy neural tissue (in which "permanent wound channel" is the key), or whether incapacitation can also be caused by a pressure wave (in which case "energy dump" becomes important).

That would mean the difference between selecting heavy, tough bullets (for maximum penetration) or lighter bullets that upset dramatically (for more energy dump) for a given caliber. So the question at issue is not point of aim, but bullet choice (and perhaps caliber choice).

RX-178
September 7, 2011, 06:17 PM
I guess I'm still not seeing what a big deal this is.

If I wanted to puncture vessels and destroy neural tissue, I'd choose an expanding bullet, since the expanded bullet creates a larger permanent wound channel, and also because of the increased likelihood that the bullet will stay inside the target. Not because of energy dump, but because of the chance that if it goes completely through, it can hit something or someone that I was not intending to cause harm.

If I wanted to cause an energy dump in the target, I'd still want the bullet to get far enough inside that it can dump the energy deep in all the important internal organs, so I'd choose (again) an expanding bullet that still has enough weight to penetrate inside where the energy dump will be the most effective.

Shadow 7D
September 7, 2011, 06:31 PM
The best explanation of this is as follows

Yes it DOES exist, there is a measurable HYDROLIC shock, just as you will get one from CPR or taking a punch (just about anywhere) and it varies, so as a wounding dynamic, it becomes controversial.

Now, the next question is what does this mean to the meat, mainly CAVITATION- or the temporary cavity as TISSUE MOVES OUT OF THE BULLETS WAY.

Shoot elastic tissue and it stretches, exceed its ability to stretch with the amount of energy dumped, and you have a nasty wound. Don't, and you have SOME tissue damage from the little bits that have a hard time stretching compared to surrounding tissue, like capillaries etc. BUT

At handgun velocities, the effect is NOT a consistent wounding dynamic.

So yes it exists
but in handgun

SO WHAT...
once again, penetration (ability to TOUCH)
then like real estate...
LOCATION..LOCATION..LOCATION
(placement placement placement)

Loosedhorse
September 7, 2011, 06:43 PM
Actually, three separate issues:

1) At certain energies (velocities), a passing bullet disrupts the tissue cells and small (capillary) vessels, producing "bloodshot" meat.

2) The temporary cavity, when large enough, can tear muscle. At lower velocities, the temporary cavity can be "small enough" that it doesn't produce the "bloodshot" effect or muscle tears, but still fractures vulnerable tissues that do not have the elasticity of muscle. Such tissues include liver, spleen, brain and perhaps the largest blood vessels (which are often fixed in place by fascia, and so are subject to sheer, rather than being able to move freely out of the way and then return as the temporary cavity forms and collapses).

3) And the question at hand: whether a "pressure wave" produced by a bullet to the chest or abdomen can be transmitted (presumably via the blood vessels) to the brain and cause immediate brain dysfunction.

Shadow 7D
September 7, 2011, 06:49 PM
Stated that way, I'd have to say NO
as I have personally seen a guy who was shot 3x by a .50BMG, and if that didn't do it, don't know what will.

Eb1
September 7, 2011, 07:05 PM
, it can hit something or someone that I was not intending to cause harm.

Know what is behind your target. Even when hunting.

Cop Bob
September 7, 2011, 07:15 PM
Sorry folks, I'm going with the Wiki quote here...

I see lots of folks quoting a lot of theory.. I have read a few of the same books.. But I know, what I know from seeing the results up close and personal.. I worked in a VERY busy Trauma Center for 2 to 3 nights a week for about 6 years.. I also have made more than one trip to the Morgue, as well as a few pretty good crime scenes.. I also have spent my whole life shooting, and running my own terminal ballistic test..For many of which my employer footed the bill...

Fact, any projectile that enters the body at speed, any speed, does so with enough force to set up some hydraulic shock. The question is how much..

There are two ways to get this shock to increase.. One is through bullet weight and size, the other through speed..

One way to increase the hydraulic shock value it through efficient bullet design.

Most handgun bullets will not effectively open, or mushroom unless they are traveling at or above 1000 FPS,, some designs, but few, will open at 870 fps, but not reliably. The old WW 180 grain Silvertip in 45ACP comes to mind here.. and the old 146 gr FBI load for 38 Spl..

If the bullet is moving fast enough to open, this expansion takes place in milliseconds.. It is a very rapid and very violent action. It places body fluids in motion, it disrupts the central nervous system. It does destroy more flesh, but only by about 10 to 15%.. Fatalities are only about 20% higher... This hydrostatic shock, HOWEVER MINOR IT MAY BE.. is what we are looking for in a defense situation.. It causes the entire nervous system to blank out.. kind of like putting your finger in a light socket.. It will cause the attacker to loosen his grip, drop what he/she is holding, to become disoriented, much like an epileptic after a seizure.. These are the minor effects, they work to our advantage.. More on that later..

The faster a bullet moves, the more violent the expansion, the more the hydraulic shock is amplified.. The greater effect upon the body..

The draw back is shot placement, abdominal shots place the most fluid in motion, however they are the least terminal, as their are fewer vital organs in the abdomen, save the liver, but even the liver is capable of sustaining major trauma, and still be repairable..

The most effective shot placement is in the chest, or close to the spine and the central nervous system (CNS)... or the "fatal T" this is the best area for placement.. It provides the most shock transfer to the the CNS.. it also provides the most fatal results.. Why, because that is where the heart, lungs, and brain live..

Does a bullet have to move at 1000, or 2000 fps to deliver this shock... no.. a good punch in the gut from a 6 year old can take your breath away... Why? because it produces hydraulic shock... It can knock the breath out of you.. while you are trying to catch your breath, is that moment of incapacitation.. you can't do anything else except try and catch your breath..

When the body is hit by a bullet, it, to varying degrees. is doing the same thing.. and the effects can range anywhere from, a grimace and a "dang that hurt".. to immediate unconsciousness..or in a good brain stem shot, drop like a sack of potatoes..

My point being, that all bullets, handgun, and rifle will produce shockwaves within the body.. the question is how much, AND how much is enough?

Well, as stated, and known by all here that, bigger is better, AND faster is better, what is best, a debate for all time.. one that will not be settled here.. Personally I think it is a combination of both..

But for someone to say that it takes a 2000 fps projectile to create hydrostatic shock... sorry, not completely so... now a 2000 fps handgun, is a bomb, and yes it most certainly creates MORE shock.. but to say that it has to move that fast to be effective... Sorry I can't go with it..

I have seen with my own eyes, a robbery suspect shredded with Black Talons, 115 gr 9mm, probably somewhere in the 12-1300 fps range.. was the damage prolific, oh yes it was nasty. was the wound channel evident? yes, through the edema, or busing of the adjacent tissue along the wound track.. was there massive damage, no not really, no torn tissues, ruptured organs, just a lot of really red, bloody meat.. any deer hunter has seen it.. I have also seen folk hit with a 32 ACP FMJ that were just as dead.. just not near as torn up... the question is, how much fight was in them after the 1st hit... or hits..

I have seen a great many others, all bear out the same thing to one degree or another, a previous poster says the same thing, and that too, is from hospital, real world observations..

There are too many studies, to many real world experiences to show that hydraulic shock is a real deal, it happens to varying degrees with all gunshot wounds.. The degree and the effect depends upon, bullet size, bullet design, shot placement, speed, how much clothing, bone encountered.. (Secondary projectiles is whole new chapter here folks).Size of the target, Drug use, excitement or adrenaline levels.. all of it is a factor as to the immediate effectiveness of a round.

Above all, the one thing that I have learned, to an ABSOLUTE CERTAINTY... that No Two Gunshot Wounds are the same, and a bullet will never do EXACTLY the same thing twice.. But it will repeat to a degree where it's outcome can be fairly closely predicted...

But even a 22 short creates a certain amount of shock... how much effect it has depends upon it's size in relation to the target..

The whole reason that we look for ammunition that will give us the edge of this Hydraulic Shock Theory, is because we seek to cause an immediate stop the the attack, of threat.. The most effective way to do that is through good shot placement, with an effective round. One that will reliably expand.. regardless of caliber..

Good ammo, good shot placement, Caliber selection of sufficient size, speed and weight to reliably do the job.. And there are a LOT of good ones out there,, Just not that many of them move at 2000 FPS in a handgun...

KodiakBeer
September 7, 2011, 07:19 PM
3) And the question at hand: whether a "pressure wave" produced by a bullet to the chest or abdomen can be transmitted (presumably via the blood vessels) to the brain and cause immediate brain dysfunction.

And the answer is "no". Not at handgun velocities and only rarely at rifle velocities. There are millions of big game animals taken every year from high velocity hunting rifles. Occasionally, you get a dramatic knock down that "might" be due to a neurological shut-down, who can really say? You simply don't see that with slower bullets.

Ole Humpback
September 7, 2011, 07:20 PM
If we assume that the ideal gas law holds (which I am not sure is valid at the combustion temperature/pressure...but for the sake of argument), then shouldn't pressure decrease inversely with volume? Since the barrel is (for our intents and purposes) approximately a right circular cylinder, the volume is Base x Height (pi r^2 times bullet position in barrel as a function of time). Perhaps as a function of time, the graph of chamber pressure might appear to be decreasing somewhat 'exponentially'. I think that as a function of volume or bullet position, it would appear inversely linear (ignoring any gas or structural non-linearities). Thoughts?

PV=nrt describes how the pressure reduces. This is somewhat trivial, but it lends itself to identifying the lose of pressure due to bullet displacement. Not much to say here, as the bullet moves down the barrel, the gases expand to fill the volume created by bullet displacement. The frame of the gun meanwhile is absorbing the gases thermal energy, in effect creating a one-two punch on pressure lose. Pressure is reduced by the bullet being moved down the barrel as well as the gun absorbing the thermal energy of the gases. I thought more on it, and inverse is the correct term for pressure lose based on bullet displacement. However, point is that there is little time for pressure to reduce and the pressure at the muzzle is significantly reduced from what it was in the cartridge.

When you say 'exponential', I believe you mean inversely proportional to a cubic or quartic. That is, x^-n is not the same as exp(-x). Your example was 2^-4 = 1/16. An exponential function grows (or shrinks) much faster than a polynomial. Again, you might be right about the exponential decay as a function of time, I just haven't given the equations much real thought.

You're correct. My vocabulary at 11pm isn't as good as it normally is:rolleyes:

Later you describe force as a pressure times an area times a time. I believe you mean an impulse (similar to momentum). I think you called it that as well. Is a 'symmetric pressure recoil force' another term for impulse or momentum? Also, I believe you mean microseconds which is only really fast, rather than picoseconds (10^-12 s), which is crazy fast.

Yes, symmetrical cartridge pressure is a specific impulse. Its the force that results from the length of time that passes when the powder (for our intents & purposes) has turned to a gas, but the cartridge hasn't deformed enough to release the bullet. Good catch on the time as well. I was trying to think of what 10^-9 seconds was, but it didn't quite come to me. Now that you mention it, that's probably too fast. Its probably nearer to 10^-6 seconds or even 10^-3 seconds.

When you describe kinetic energy, I believe you mean KE = 1/2 m v^2. This will actually produce substantially larger numerical quantities (in Imperial or SI units) than the mass times the velocity (which is momentum, a useful value for the discussion of recoil).

I was trying to point out that KE for the bullet will always be larger than the momentum of recoil. Forgive me, late night physics is always fun but I tend to miss a few things (I get it in my head, but it doesn't always get typed correctly).

Anyway, this is a good discussion. I enjoyed your analysis about rigid structures in addition to the mass relationships between momentum transfer. You know you are having fun when you start discussing material non-linearities and structural dynamics on a gun forum!

I'm interested to hear your thoughts about my pressure vs time and pressure vs bullet position hypothesis.

Cheers!

I always enjoy a good structural dynamics talk. Keeps the grey matter flowing:)

but when all is said and done the same energy is directed backwards as is driving the projectile forwards

Issac Newton's Second Law still applies, but not in a linear fashion. Once the bullet is released from the cartridge, the pressure becomes asymmetrical with a majority of the pressure creating force on the bullet base (remember, pressure follows the path of least resistance). The remaining force of the pressure is converted to either tension or compression forces that are reacted by the grain structure of the metals in the gun with very little of that force being applied to the cartridge base.

Lets use the 357 Mag as an example. For simplicities sake, and the fact that calculus would take forever to do (let alone create a formula for), the pressure is constant and only observed at the point in time when its at its maximum: symmetrical case pressure at the exact moment the cartridge releases the bullet.

First off, the knowns/assumptions:

357 max case pressure: 35000psi
357 cartridge base area: .1127"^2
Length of time for symmetrical case pressue: .005s
Pistol weight: 2lbs
Recoil Energy of a 158gr round at 1250fps: approx. 9ft/lbs

Second, equations to solve problem:

Recoil: F=ma
Specific Impulse: F=PAλ

Start by finding a for recoil:

9ftlbs/2lbs=4.5fps^2 acceleration

Next, find F for specific impulse:

35000psi*.1127"^2*.005s= 19.72lbs

Beyond this, recoil is a net force and I for the life of me can't come up with the formula to explain how force on the cartridge base gets turned into ftlbs.

THplanes
September 7, 2011, 07:57 PM
First off, you need to understand that the bullet kinetic energy is not reacted into the gun, rather it is the force of rapid pressure change of the burning powder in the cartridge. When the primer is struck, it ignites the powder, which rapidly burns and changes into a gas. Using the combined gas law of PV=nrt to determine cartridge pressure, we can then set about figuring out the forces being translated into the frame of the gun and bullet..

The powder gasses provide the energy that acts on the bullet and the gun. PV=nrt is making it more complicated than it needs to be. All we need is the equation for momentum.

p=mv

In this case the momentum of the gun is equal to the momentum of the bullet plus the momentum of the powder gasses.


Since pressure is defined as P=F/A, we look at the internal surface area of the cartridge and the surface area of the base of the bullet. Once these two are known, then we can determine forces acting on the cartridge and bullet. The forces inside the cartridge prior bullet release are symmetrical, equal amounts of force all around the cartridge. However, when the bullet is released the forces are asymmetrical, most of the force acts on the bullet and not on the gun..

Pressure doesn't tell you much without the frictional drag between the bullet and the barrel. The part I put in bold is simply wrong. The force acts equally on the gun and bullet until the bullet leaves the barrel. Once the bullet leaves the barrel the momentum of the powder gasses acts primarily on the gun.


As the bullet moves down the barrel, pressure is being reduced due to an increase in volume (as the bullet is displaced, gases take its place). The farther down the barrel the bullet goes, the less pressure there is acting on the gun. As the pressure is decreasing, the area for the pressure to act on is increasing which means the force is decreasing. Since both pressure & area are square units, pressure decreases by a square root for each unit increase in area (a 1 unit increase in area results in a 4 unit decrease in pressure, a 2 unit increase in area means a 16 unit decrease in pressure, ect.). The progression of pressure reduction is not linear, its exponential. This results in an exponential reduction of force the farther down the barrel the bullet goes..

I'm not sure why you are using area here. Pressure and volume have a direct but inverse relationship. If you double the volume, you cut the pressure in half. You can see this from the PV=nrt. If you hold nrt constant, then the the value of PV is also a constant. The increase in volume leads to a linear decrease in pressure. There is another very serious problem with your analysis. nrt is not a constant. More gas is being produced as the powder burns. Therefore the the pressure decrease, or increase, is related to the increase in volume and the burning rate of the powder. A powder that is optimal for a certain cartridge will usually show a slower decrease in the pressure verses time curve. This gives you a higher average pressure and more velocity.


Once the bullet leaves the barrel, all the remaining pressure exits the muzzle following the path of least resistance since the primer was struck. The path of least resistance in the case of firing a gun for the cartridge gases is to push the bullet out of the gun..

No, the force acting on the bullet and gun is the same until the bullet exits the barrel. Powder gasses for a service pistol will be around 5-15% of the total recoil. So the gun will have this amount of momentum more than the bullet.


Now onto recoil. Recall how the pressure goes from symmetrical to asymmetrical once the bullet is released, this defines the recoil you feel. To define the symmetrical pressure recoil force, you need to add another variable: time. The symmetrical pressure recoil force is F=PAλ. λ is the time that is experienced at that specific PA. Since λ in the case of symmetrical cartridge pressure is defined in pico-seconds (millionths of a second), the max recoil force attainable is extremely low. This is called a specific impulse. The forces during a specific impulse can be tremendous, but short time frames drastically reduce the actual force of the impulse...

This section is just about hopeless. I'll admit I don't know whether F=PAλ is an appropriate equation. If it is the only way it can be used is with an integral and λ would be infinitesimally small as pressure is constantly changing. Pressure does not define felt recoil or total recoil. Total recoil is defined by momentum. The momentum of the gun will equal the combined momentum of the bullet and the powder gasses. The felt recoil will be determined by the mass of the gun and time frame over which the momentum is transfered to the gun and your hand. For recoil specific impulse, symbolized by I, is better defined as the change in momentum. Since initial momentum is 0, the change in momentum of the gun is equal to the momentum of the bullet and gasses and is equal to the total recoil. For a revolver the gun has about 90% of the total recoil when the bullet exits the barrel. So you hand will also experience the recoil in this same time. For a semi-auto the gun also has about 90% of the recoil when the bullet exits the barrel. But it initially goes to the slide. Then the slide uses the recoil spring to transfer the momentum to the rest of the gun and your hand. This spreads the recoil over a longer time and will make the felt recoil less.

Edit to add - F=PAλ is completely inappropriate as you're using it. You seem to bee using it to represent recoil that occurs between ignition and when the bullet starts to move. There is no recoil generated during this time. Recoil is not generated until the bullet starts to move. You want an obvious example, look at a propane cylinder. Lots of pressure and time, but it just sits there.


Also, the cartridge base that pushes against the firearm itself is exponentially bigger than the base of the bullet, which leads to lower force imparted on the frame of the firearm than the base of the bullet during the specific impulse. Once the cartridge pressure becomes asymmetrical, the force acting against the gun drops exponentially..

This is actually back wards. Since F = PA, or force = pressure x area, the force on the breach face is is higher than the force on the bullet base. I know it's counter intuitive, but pressure is not the cause of recoil. The movement of the bullet and powder gasses determine recoil.

Edit to add - most service pistol cartridges have a straight or slightly tapered case, .357 sig excepted. So there is little difference between force on the breach face and the bullet base.


Now, to sort out kinetic energy vs recoil. Kinetic energy is F=ma. In the case of a firearm, a is acceleration with a given direction: velocity. Convert grains to pounds and multiply by muzzle velocioty to get ft/lbs of kinetic energy. As for recoil, the specific impulse that acted upon the cartridge base is greater than the weight of the gun. Subtract out the weight of the gun in pounds and you get the actual recoil force in pounds. Since the body isn't a rigid structure, your hand & arm displace to absorb the small amount of force involved..

kinetic energy = 1/2 m v^2
momentum = mv

Acceleration is not velocity. Acceleration is the rate change of velocity. Pounds is not a unit of mass, it's a unit of force. You have to change to slugs and use the right equation and diners ready so I'm not going there.


As for hydraulic shock, apply the same math plus the average speed of sound in flesh to determine the rate at which the bullet kinetic energy will be imparted, determine the λ for bullet/tissue interaction time and you get a good idea of how much hydraulic shock will be imparted by any given round.

The speed of sound is not really that important. You really need the energy and the penetration depth to get an average for energy transfer. To get specific about the change, it's best to study the size and shape of the temporary stretch cavity.

Shear_stress
September 7, 2011, 08:15 PM
Ole Humpback, I don't mean any disrespect but I've got a few bones to pick with some of your statements.

Yes, symmetrical cartridge pressure is a specific impulse.

Pressure is not an impulse. Impulse is a change in momentum with units of force*time. Specific impulse is a term from rocketry and has little relevance here (it's equal to force/(mass flow rate*g)).

I was trying to point out that KE for the bullet will always be larger than the momentum of recoil.

KE and momentum are different physical quantities and their comparative numerical values have little meaning.

Issac Newton's Second Law still applies, but not in a linear fashion. Once the bullet is released from the cartridge, the pressure becomes asymmetrical with a majority of the pressure creating force on the bullet base (remember, pressure follows the path of least resistance). The remaining force of the pressure is converted to either tension or compression forces that are reacted by the grain structure of the metals in the gun with very little of that force being applied to the cartridge base.
Regardless of whether its application is linear over time, Newton's 3rd law still applies at any given instant. Superman cannot fly because he cannot generate a net force against anything. Likewise, if the chemical explosion inside the chamber generates a force on the bullet, it generates the same force on the gun. While the bullet is stationary in the case, the chemical energy generated by the powder is transferred into heating the cartridge/chamber and slight case deformation. However, the instant the bullet starts moving, the gun must start moving in the opposite direction, though slower on account of its greater mass. In other words, there is a net force on both the gun and the bullet. If there weren't, there would be no recoil.

Recoil: F=ma
Specific Impulse: F=PAλ

Again, impulse is in units of force*time. Impulse includes, but is not, a force.

Edited to add: I didn't see THplane's excellent post while composing mine!

Loosedhorse
September 7, 2011, 08:24 PM
the pressure becomes asymmetrical with a majority of the pressure creating force on the bullet base (remember, pressure follows the path of least resistance).However, when the bullet is released the forces are asymmetrical, most of the force acts on the bullet and not on the gun
No.

As the bullet leaves the barrel, the previously "closed" pressure system develops a "leak" at the bullet-muzzle gap. Pressure will therefore be lost first there, with that loss being transmitted quickly (at the speed of sound) to the breech face.

So, the bullet will "feel" the loss of pressure first.
And the answer is "no". Not at handgun velocities and only rarely at rifle velocities.Well, that is currently in dispute. The authors answer that point (about deer not often experiencing "shock" drop) by supposing that deer's dependence on head- and antler-butting dominance games has made them less susceptible to such shock than humans.

I'm not saying that's true, but it is their theory.

1stmarine
September 7, 2011, 08:27 PM
the capability of a round to inflict hydrostatic shock has nothing to do with the speed alone and everything with the amount of energy released in the medium (in this case the body of the target) in function of penetration and time (deceleration).
Ideally there would be massive expansion and not over penetration (loss of energy).
A 300 grain 50 caliber hp 'soft' slug at 900fps will produce a killer wave vs a .22 55gr fmj at 3000fps that might cut clean if it doesn't tumble.
Normally more speed means more energy but if there is over penetration all potential is lost.
I have seen both type of wounds and trauma and even before I read the Cornell University report it didn't take too much to understand the simple effects of physics. I see if I can find it and post it here.

Prosser
September 7, 2011, 08:44 PM
A couple different ways to create shock.

One that doesn't really get mentioned much is:

http://www.kettering.edu/physics/drussell/Demos/doppler/doppler.html

Depending on bullet design, weight and velocity a similar shock wave would occur in fluid mediums as well.

I suspect as the bullet maintains velocity through the liquid medium it can create a similar pressure wave inside the body.

http://www.grosswildjagd.de/penetrat.htm

The above link has a bunch of references to bullets designed to maximize
that shock wave.

Kind of fills in a missing part of the discussion.

To elaborate: as velocity through the target increases, so does the wound channel. I am pretty sure this is due to the pressure wave created by the bullet as it goes through the medium.
The design of the nose of the bullet is vital for stability through the target, and really effects how the pressure was is created, and how much of one is created.

The problem I see with most service caliber hollow points is the bullet expands suddenly: It also slows down VERY quickly, since the bullet hasn't enough mass to maintain it's velocity through the target.
You get an increase wound cavity usually right after penetration, but, sacrifice wound channel after the bullet expands and deaccelerates. One of the great things about 45 caliber or larger pistols is that
they can be loaded with heavier hollow points, that have a much better chance of moving through the medium, expanding, and continuing to create a pressure wave as they go through the target.

An alternative approach for service calibers is to use a truncated nose, or some sort of flat point that still feeds, in a non-expanding bullet. At over 1350 fps, LFN's tend to widen, and create a larger then caliber
flat point bullet that still penetrates straight, and maintains it's velocity through the target. Lee Jurras used to do this with the 44 magnum. He used silouhette flat points at 1900 fps, 185 grains, and the speed and
shock wave of the bullet did the damage. Using this method he gets a large, long wound channel, without the various problems associated with HP's. I've often considered, and do with 9MM, use 147 Grain Flat points
as an alternative, or in conjunction with 147 grain HST. I'm not convinced that the standard party line on penetration of 12-14" is enough, since after the bullet expands, about the last 6 inches produces minimal wound
channel, because the HP is first expanded, and second unstable, and third moving very slowly.

Buffalobore makes a 45 ACP offering similar to what I'm thinking of, though it's a bit heavy:
http://www.buffalobore.com/index.php?l=product_detail&p=214
Still, it makes the .45 ACP=45 Colt, the Holy Grail standard for service calibers.

Bobson
September 7, 2011, 09:54 PM
If it doesn't penetrate the target completely, then the round dumped all of its energy. That is the physics fact for the day.

If you can get something going fast enough, even air, it will kill. Bombs kill via shockwave as an example. That is 100% pure hydrostatic shock since there is no other way for the wave to hurt you. Also, if you are in a swimming pool (or water) when explosives go off, you'll feel it much more than if not. It doesn't take much to kill in water.

The FBI Miami shootout. One of the cops got hit in the neck with a 5.56. It passed through, didn't hit anything major, but it dropped him and he spent the rest of the gunfight paralyzed. Apparently the shock wave separated his spinal column causing it to pinch a nerve. Very lucky.

I've seen ballistics gel tests, and if they are similar to soft tissue, I can say that having my stomach shoved into my chest looks pretty uncomfortable to me, even if it is temporary. I've had bad gas before, it was temporary too, but I almost ended up in the ER.

Too many variables to say for certain how damage occurs and what does what, but I can say that it is very plausible.
Lots of outstanding points to consider here.

THplanes
September 8, 2011, 12:57 AM
Shear_stress and Loosedhorse already covered most of the problems in this post so I'm going to tackle this one.

Lets use the 357 Mag as an example. For simplicities sake, and the fact that calculus would take forever to do (let alone create a formula for), the pressure is constant and only observed at the point in time when its at its maximum: symmetrical case pressure at the exact moment the cartridge releases the bullet..

It doesn't take 35000 psi to seat a bullet on a loading press. It does not take 35000 psi to get the bullet moving. As soon as the pressure causes enough force to
1) expand the brass or
2) force on the base of the bullet exceeds the bullet pull force or
3) a combination of these happens
the bullet starts moving. The bullet doesn't wait for max psi to start moving. Then it hits the lands in the barrel. At this point the acceleration of the bullet slows because of the engraving force of pushing the bullet into the lands. Then the bullet accelerates again. The attempt to use the 35000 psi as some magical number just doesn't work.


First off, the knowns/assumptions:

357 max case pressure: 35000psi
357 cartridge base area: .1127"^2.

You've got some explaining to do here. You come up with .012701 sq-in.
It should be

a = pi r^2= (3.14)(.1785)^2 = .1 sq-in.


Length of time for symmetrical case pressue: .005s.

Even if this number correct it is basically meaningless. Recoil doesn't start until the bullet moves.


Pistol weight: 2lbs
Recoil Energy of a 158gr round at 1250fps: approx. 9ft/lbs

Second, equations to solve problem:

Recoil: F=ma
Specific Impulse: F=PAλ.

Specific Impulse is a measure of the efficiency of a rocket motor. While it could be applied to the powder, it has little if anything to do with recoil.


Start by finding a for recoil:

9ftlbs/2lbs=4.5fps^2 acceleration.

9ft/lbs is a measure of kinetic energy. It's not a measure of force so it's use here is wrong. The 9ft/lbs comes from

KE = 1/2mv^2.

KE and force are not the same thing.


Next, find F for specific impulse:

35000psi*.1127"^2*.005s= 19.72lbs.

Again, this is simply meaningless


Beyond this, recoil is a net force and I for the life of me can't come up with the formula to explain how force on the cartridge base gets turned into ftlbs.

That's good because it doesn't. You might want to do some reading on a few formulas

F = ma
KE = 1/2mv^2
Momentum = mv
Impulse = change in momentum.

Since the initial velocities of the all components is 0 fps,
Impulse = momentum = momentum of pistol = momentum of bullet + momentum of powder gasses

I think Impulse or free recoil energy or free recoil velocity are all useful measures of total recoil. These can all be calculated from the above equations. You need to know the gun mass, bullet mass, powder mass, bullet velocity and powder gasses average velocity. For a typical service pistol you can SWAG the powder gasses at about 2000 fps.

Friendly, Don't Fire!
September 8, 2011, 06:43 AM
And the answer is "no". Not at handgun velocities and only rarely at rifle velocities. There are millions of big game animals taken every year from high velocity hunting rifles. Occasionally, you get a dramatic knock down that "might" be due to a neurological shut-down, who can really say? You simply don't see that with slower bullets.
I think that is a rather dogmatic statement, that handguns cannot cause any hydrostatic shock sufficient enough to cause damage to organs connected via arteries, vessels, etc.

My 500 Magnum is "all-handgun" and has much more power and energy than a lot of rifles with which people use to CLEANLY-kill big game all the time!

MachIVshooter
September 8, 2011, 11:50 AM
It causes the entire nervous system to blank out.. kind of like putting your finger in a light socket.. It will cause the attacker to loosen his grip, drop what he/she is holding, to become disoriented, much like an epileptic after a seizure.. These are the minor effects, they work to our advantage.. More on that later..

Someone sticking a red hot poker on your skin or giving you a nasty nurple will also cause you to cease whatever you're doing and most likely drop whatever is in your hands. It is a disruption to the nervous system, but not a physical one-it's a psychological one; Our nervous system cannot command any task other than reflex when sudden, excruciating pain is sensed.

There are exceptions to that shutdown rule, of course. One is adrenaline; People in extremely high-stress situations often don't even realize they've been injured until it's over. This includes being shot.

The other is simply mental preparation. This also incorporates adrenaline to some degree, and there are limits (entirely dependent on the person), but some people can experience incredible amounts of pain without loosing motor function and conscious thought if they're ready for it.

About the only type of trauma that won't cause people to let go of things is electrical shock. Not because it doesn't disrupt the nervous system, but because that electrical impulse causes every muscle to contract. Since the muscles that close the hand are far stronger than the ones that open it, the hand remains firmly clenching whatever was in it. Of course, the entire body tends to go limp noodle once the electricity ceases to flow. How long it takes the nervous system to recover depends on the amount of electricity and whether it caused only temporary disruption of neural pathways or permanent nerve damage.

Does a bullet have to move at 1000, or 2000 fps to deliver this shock... no.. a good punch in the gut from a 6 year old can take your breath away... Why? because it produces hydraulic shock... It can knock the breath out of you.. while you are trying to catch your breath, is that moment of incapacitation.. you can't do anything else except try and catch your breath..

No, that punch produces blunt trama, and the diaphragm is very susceptible to it.

Blunt trama and hydraulic shock are not the same thing.

the capability of a round to inflict hydrostatic shock has nothing to do with the speed alone and everything with the amount of energy released in the medium

Incorrect. A two-ton sedan moving at 2 MPH produces far more energy than a handgun bullet, yet if you are standing against a wall and that car rolls into you (Immediate "energy dump"), you're not going to experience any injury from hydraulic shock.

energy is the product of mass and velocity, but in and of itself is not a wounding mechanism. Miniscule obejcts at extreme velocities and very large objects at very low velocities can both produce energy equal to a bullet, but cause far less injury (if any). It is a balance between the mass and velocity that makes bullets so effective in damaging tissue.

If you really believe it's all about energy, try comparing a hot 10mm load and a .17 Remington on water jugs or gelatin. Both produce about 750 ft/lbs, but one has a much more violent effect on liquid or semi-liquid (tissue-like) mediums. This is the result of velocity; The hydraulic shock effect is relatively minimal at the ~1,400 FPS 10mm velocity, but very dramatic at the 4,200 FPS .17 velocity.

I hate using kills on small animals as a comparison, but in this case I think it makes the point. I've shot plenty of pesky rabbits with both of these rounds (180 gr. Golden Sabre at 1,406 FPS for 792 ft/lbs and .17 Rem. with a 20 gr. HP at 4,245 FPS for 800 ft/lbs). While the 10mm tore them up something fierce, the .17 literally blew them apart. As in, a leg over here, 15 feet to the right a head with shoulder and half a leg, 20 feet back a length of intestine......

Both rounds produce hydraulic shock that exceeded the tiny animal's tissue elasticity, but the high velocity rifle round produced so much more that it was effectively like putting a small bomb inside the animal.

KodiakBeer
September 8, 2011, 12:18 PM
Well, that is currently in dispute. The authors answer that point (about deer not often experiencing "shock" drop) by supposing that deer's dependence on head- and antler-butting dominance games has made them less susceptible to such shock than humans.

I'm not saying that's true, but it is their theory.

Well, people shoot lots of critters other than deer. Perhaps pigs might answer that question better than deer. I have no experience with pigs, but there are plenty of people who do. I suspect their answer will be the same one that deer hunters have.

Loosedhorse
September 8, 2011, 12:19 PM
Well, there certainly is a language barrier here, to some extent.

We seem to have "hydrostatic shock", "hydrodynamic shock", and "hydraulic shock" as terms...and I'm not sure that there's general agreement on what any of them are, and whether they are different. The Courtneys use "Ballistic Pressure Wave," and wiki uses hydrostatic shock.

The ability of a 4200 fps round to disintegrate a small rodent would seem to be (as has been stated) due to the temporary cavity being bigger than the maximum elastic expansion of the small animal. That may fall under "hydrostatic" (etc.) shock, but it is not the ballistic pressure wave in the sense the Courtneys mean.

Let's talk about (brain) concussions for a moment. Their mechanism is not well understood. MRIs and similar structural scans done on patients with traumatic concussions often show NO abnormal brain findings: no bleeding, bruising, or swelling. So, what's causing the dysfunction?

Given that we are unsure of the mechanism of concussion, I think it is premature to say that a ballistic pressure wave "couldn't possibly" cause a concussion.No, that punch produces blunt trama, and the diaphragm is very susceptible to it.

Blunt trama and hydraulic shock are not the same thing.Perhaps we are having another language problem: what does "blunt trauma" mean in this context? Obviously, the diaphram is not directly struck by a fist to the gut, but the force of the impact is transfered to the diaphragm by over-pressure of the abdominal cavity/displacement of the abdominal contents into the diaphragm (with those contents behaving like a viscous liquid).

I think I'd need a clearer definition of both "blunt trauma" and " hydraulic shock" to decide which of those affect the diaphragm after an abdominal blow. Maybe it's both (that the blunt trauma is transmitted via a hydrostatic mechanism, for example).I suspect their answer will be the same one that deer hunters have.You could be right, but how many hunters use less penetrative, fragmenting bullets on pigs? It's intersting to speculate whether or not we'd see more "shock drops" on pigs if we did. However, the ethics of hunting demand that we kill the pig as quickly as possible, not "stop him" immediately, as in the case of SD.

One of the central arguments here is that the "only dependable way" to stop a human attacker is to deilver a wound that either kills him or leaves him with permanent, devastating neurological damage. And yet it seems that a significant number of attackers are stopped by handgun wounds that are not that severe. The current theory is that such "stops" are 100% psychological.

KodiakBeer
September 8, 2011, 12:28 PM
You know, it occurs to me that veins and arteries have "valves" every few inches. Junkies regularly blow these out leading to collapsed veins. This is something easily recognized by a physician, and surely by a coroner.

If gunshot wounds were blowing enough pressure through the vascular system to create damage and neurologic shock far from the point of impact, I'm sure coroners and surgeons would have noted that long ago.

MachIVshooter
September 8, 2011, 12:40 PM
Obviously, the diaphram is not directly struck by a fist to the gut, but the force of the impact is transfered to the diaphragm by over-pressure of the abdominal cavity/displacement of the abdominal contents into the diaphram (with those contents behaving like a viscous liquid).

There's your answer, and it is still direct physical contact causing the diaphragm to be affected.

To say that it is not the impact of the fist that causes this would be like saying that the torque applied by the hand turning the screwdriver did not loosen the screw. Transmission of force/impact through a medium does not change the mechanism. With the screwdriver, it is still torque that causes the screw to turn. With a gut punch, it is still blunt impact that causes the diaphragm to be affected. The medium can amplify or dissipate, but does not alter the mechanism. It is still torque that turns the screw, and it is still impact that "knocks the breath out of you"

Loosedhorse
September 8, 2011, 12:43 PM
KB, several things.

Coroners are asked to determine cause of death. They see a gunshot wound, they see exsanguination? Not going to put distant veins under a microscope. And since we are looking a ballistic pressure wave as a possible cause of incapacitation, not death, it is unlikely a coroner would meet a temporarily incapacitated person.

Veins are extremely elastic, arteries less so; neither would be damaged visibly by a momentary pressure wave (as distinct from a temporary cavity stretch). (BTW, arteries have no valves; and venous valves are fairly weak, as anyone with varicose veins will attest.)

And again, you are demanding evidence of damage from a mechanism that may not produce visible damage at all; just concussion-like incapacitation....displacement of the abdominal contents into the diaphragm (with those contents behaving like a viscous liquid). There's your answer, and it is still direct physical contact causing the diaphragm to be affected.
Well, but...

As I understand it, a hydraulic system works by taking force applied to a master cylinder here and trasmitting it via displacement of hydraulic fluid from the master cylinder through lines to a slave cylinder over there.

So if your punch's force is transmitted by displacing a fluid-like material against the diaphragm...why is that not hydraulic?

And, no: there is NO direct physical contact between the fist and the diaphragm (unless your fist penetrates the abdomen and touches the diaphragm). At least that is my understanding of the term "direct contact."

snooperman
September 8, 2011, 12:52 PM
veins take blood away from body structures toward the heart and arteries takes blood with oxygen and nutients TO body structures. There is much medical evidence that there is hydrostatic shock in arteries from gun shot wounds to one degree or another . This can affect blood flow to the brain from pistol shots to the chest creating loss of neural blood supply, causing neural shock and death. Read " Hydrostatic shock" on wikipedia and other sites that give medical evidence for this phenomenon.

KodiakBeer
September 8, 2011, 01:16 PM
Veins are extremely elastic, arteries less so;

Yet, if you work in an ER as I have done, you note those blown veins made just by injecting a couple of CC's of fluid without releasing the tourniquet. They are visible from the outside of a body and are diagnostic of an IV drug user. This is pretty basic ER stuff that even techs and nurses will recognize.

I'm sure it would be noted by a coroner if they were present in gun shot wounds.

Loosedhorse
September 8, 2011, 01:51 PM
You are correct. But that is rupture of a vein caused by low-pressure, large-volume over-filling. The mechanism of a pressure wave is a momentary high pressure/low volume change; further, it is likely that the pressure wave would travel both within and along (outside) the vein, so there is no pressure differential to stretch the vein.

The importance of the vessels in the theory is that they allow the fluid pressure wave to reach the CNS, which is otherwise pretty well shielded by bone.

Shadow 7D
September 8, 2011, 03:12 PM
Ok, but do you realize that BLOOD does not enter, EVER the CNS, and it causes bad thing, there are membranes etc. that form a 'blood brain barrier'

boys, we are talking jedi 'force' here
really lets stick to the stuff that matter instead of trying to develop some super round or debating intangibles

there may be a mechanism, but every RELIABLE study, and hunters account don't indicate some super CONSISTENT force, rather the same ol put a hole through something vital.

Loosedhorse
September 8, 2011, 04:55 PM
Ok, but do you realize that BLOOD does not enter, EVER the CNSWhat an odd thing to say.

Of course blood enters the CNS--otherwise the brain and spinal cord would have no oxygen or nutrients, and could not exist. The blood that enters the CNS is (of course) contained within blood vessels.

What is meant by "blood-brain barrier" is that the CNS capillaries (unlike many capillaries elsewhere) do not leak large proteins (like albumin and immunoglobulins) into the surrounding tissue; small molecules (like oxygen and glucose) do cross the barrier.

But the blood-brain barrier would provide no protection from a pressure wave traveling along the CNS vessels.

brickeyee
September 8, 2011, 05:10 PM
Another thing to keep in mind is that the pressures needed to disrupt nerve operation are VERY small.

The slight swelling around a damage site in MS creates enough pressure to disrupt nerve function over a few mm away.
this is one of the reasons that MS symptoms can appear to fade short term, but there can still be long term damage.

Nerves can also depolarize from physical blows.
just about everyone has bumped their 'funny bone.'
The slight impact causes the nerves to depolarize.
We perceive it as a 'shock' or any of the other hundreds of descriptions used.
We notice it because there are a lot of sensory nerves, but you may also notice that you cannot move certain portions of your hands after the blow.

Being knocked unconscious by a blow to the head is thought to have a similar physiology.
The nerves in the brain massively depolarize and stop working for a brief period.
Since these nerves are basic functions, you may not feel anything but will be unconscious.
As the nerves re-polarize and begin functioning you awake.

A blow that causes you to 'see stars' likely affected the visual paths in the brain, or the occipital lobes at the back of the head.

tipoc
September 8, 2011, 06:53 PM
We seem to have "hydrostatic shock", "hydrodynamic shock", and "hydraulic shock" as terms...and I'm not sure that there's general agreement on what any of them are, and whether they are different. The Courtneys use "Ballistic Pressure Wave," and wiki uses hydrostatic shock.

Which is a part of the challenge. There is no general agreement on what is exactly being discussed and so there is no general agreed on terminology. So folks on both sides can argue past each other pretty easily. It's also possible for claims to gain some traction and have a certain shelf life that don't deserve it, due to misunderstanding. I'm referring here to the claim that a fella or animal shot in the hip, or foot or shoulder, with a high powered rifle round can be killed or knocked out due to a "pressure wave" that reaches the brain and bursts capillaries there, etc. This latter bit was a theory of Roy Weatherbys ,and some others, a number of decades back.

tipoc

MachIVshooter
September 8, 2011, 07:23 PM
As I understand it, a hydraulic system works by taking force applied to a master cylinder here and trasmitting it via displacement of hydraulic fluid from the master cylinder through lines to a slave cylinder over there.

That is correct, but don't confuse force with energy. Just because they are denoted with the same measurement (force is actually lb-ft/lb, poundals or other SAE and SI units) doesn't mean that they are synonymous. Kind of like ounce-both a mass and a volume unit, but 16 fluid ounces of petroleum oil does not weigh 1 pound, and a pound of mercury will not fill a pint container.

As well, a hydraulic system on a machine is closed and has a minimum of expandable chambers (namely the hoses, which don't expand much) so the pressure is transmitted with minimal loss. In a living organism, however, all of the tissues are compressable or elastic, especially the largest organ that contains it all-the skin. So when pressure is applied to a particular point on/in the body, the tissue and/or fluids that occupied that space simply move elswhere, and the pressure is largely dissipated over a much greater area than that being compressed.

As for the hydralic shockwave itself, we'll assume for the moment that the body is filled with fluid. The pressure created is obviously greatest at point of origin (bullet's meplat). Well, a bullet is very small, and the pressure will drop exponentially as the wave moves outward, and it also does so in a semi-spherical pattern. So that shockwave's energy and velocity is reduced exponentially as it moves further from the point of origin. Further reducing the actual effect of that shockwave is the fact that no soft tissue in the human body is truly rigid.

I certainly don't have hard figures on how much pressure a what velocity various organs and tissues can withstand before tearing/rupturing, but my own eyes and the experience of many others (experts included) seems to indicate that the hydraulic shock generated at normal handgun velocities is insufficient to cause the kind of peripheral wounding associated with high velocity rifle bullets where man-sized targets are concerned. Obviously, the aforementioned bunny simply lacks the overall mass to absorb the temporary cavitation caused by a handgun bullet-but as I mentioned in another thread, the affects of a rodent shot with a large caliber handgun are comparable to a human taking a howitzer round by scale. The temporary cavity at a given velocity is proportionate to the projectile size, so a 2" thick bunny getting hit with a .45 caliber bullet is like a normal sized person taking a 120mm shell.


So if your punch's force is transmitted by displacing a fluid-like material against the diaphragm...why is that not hydraulic?

I suppose we need to define fluid-like, because unless something is seriously wrong with you, your abdominal cavity is not filled with liquid. Are you considering internal organs to be fluid-like? Because I don't; They're a solid mass composed of cells. The cells may be primarily fluid in composition, but the membrane contains that fluid (a "sack", if you will). The only place where there is fluid within the torso (aside from blood in the vascular system) is between the membranes of the diaphragm (and boy does it hurt when an area geos dry [pleurisy]) But it's only a thin, lubricating amount.

Eb1
September 8, 2011, 08:34 PM
Can you not think of it like this?
Take fire cracker and ignite it on the ground or empty can. Small damage.
Put that same fire cracker in a can full of water and you have a lot more damage and force given off.

Loosedhorse
September 8, 2011, 08:35 PM
Are you considering internal organs to be fluid-like? Because I don't; They're a solid mass composed of cells.They're a fluid-like medium, in that if you strike them you get a shock wave to propogate. The standard ballistic "tissue stimulant" is a 10% gel, and we (along with everyone else) can argue whether a gel is "most like" a solid or a liquid. But there is little doublt that when you stirke a gel, you get a noticeable wave.The only place where there is fluid within the torso (aside from blood in the vascular system) is between the membranes of the diaphragm (and boy does it hurt when an area geos dry [pleurisy])Some false statements here.

Theres lots of fluid in the torso: fluid in the stomach, in the intestines--the intestines actually "float" in peritoneal fluid. As for the tissues themselves, they not only have fluid within the cells, but also "interstitial fluid" between the cells. And the cell membrane is also not solid.

Pleurisy is inflammation of the pleural space, and is typically accompanied by excess fluid there; it is not the pleura "going dry."

I'm not convinced the "pressure wave" theory is correct; but those who wish to convince people it's false seem to be in possession of a lot of anatomic misinformation.

MachIVshooter
September 8, 2011, 11:15 PM
They're a fluid-like medium, in that if you strike them you get a shock wave to propogate. The standard ballistic "tissue stimulant" is a 10% gel, and we (along with everyone else) can argue whether a gel is "most like" a solid or a liquid. But there is little doublt that when you stirke a gel, you get a noticeable wave.

I won't argue that you do cause a pressure wave when you strike soft tissue, but to that end, things that we consider true solids will also twist/contort with pressure wave, albeit not like soft tissue. However, I do not consider something that cannot flow to be a fluid/liquid; A kidney or lung does not sublime into a puddle when removed from the body and placed on a table. Internal organs and other soft tissues, similar to ballistic gelatin, exhibit properties between a liquid and a solid. They are soft and easily distorted, but more rigid than a substance like pudding or any true fluid.

Theres lots of fluid in the torso: fluid in the stomach, in the intestines--the intestines actually "float" in peritoneal fluid.

True. I suppose I should have been more specific in saying that the only part that is full of fluid is the Pleura. The stomach has only a small amount of digestive fluids that do not occupy it's entre space, nor is the peritonial "sack" full.

As for the tissues themselves, they not only have fluid within the cells, but also "interstitial fluid" between the cells. And the cell membrane is also not solid.

No argument. Just that those fluids are all separated by membranes or in between the cells; they do not constitute a significant reservior.

Pleurisy is inflammation of the pleural space, and is typically accompanied by excess fluid there; it is not the pleura "going dry."

Poor wording, it's just what I've always referred to the phenomenon as when it is that momentary occurance of the membranes sticking together that causes a sharp pain when breathing, but goes away relatively quickly. I'm not a doctor. lol. Just spent a fair amount of time in A&P books.

brickeyee
September 9, 2011, 11:46 AM
However, I do not consider something that cannot flow to be a fluid/liquid; A kidney or lung does not sublime into a puddle when removed from the body and placed on a table.

But they do flatten out and distort their shape vs. being supported in the body.

A water balloon would be a good example.
What percentage of the contents is water?
How does it behave when struck or force is applied?

Our tissue is overwhelmingly water, with cell membranes giving it some shape and form.

When it is struck, especially by fast moving objects like bullets, it behaves as a gel.

A material that is somewhere between a pure liquid and a solid.

Bones behave closer to a solid, but still contain marrow and pother cells that are NOT a solid (calcified).

Is cartilage a solid?

Shawn Dodson
September 9, 2011, 12:45 PM
"The Courtneys" are largely responsible for the recent, fresh looks at this theory:

Suggested reading - http://www.m4carbine.net/showthread.php?t=34407

KodiakBeer
September 9, 2011, 12:53 PM
The importance of the vessels in the theory is that they allow the fluid pressure wave to reach the CNS, which is otherwise pretty well shielded by bone.

I'll point out again, that blood vessels are not empty hoses. Every few inches is a valve and if those valves are overcome it can be seen even from the outside of the body. If you know a current or former IV drug user, take a close look at their arms. Most of them will have concavities where their veins are, instead of the normal convex appearance of a healthy vein.

Of course, you wouldn't see this on an artery since they lie deeper in the body, but coroners would certainly note it on an autopsy.

Shawn Dodson
September 9, 2011, 01:10 PM
The importance of the vessels in the theory is that they allow the fluid pressure wave to reach the CNS... Vessels are not rigid pipes. They are elastic, which stretch and dampen the amplitude of the "blood pressure spike". They are also connected to other vessels, which disperse and dissipate the "blood pressure spike". In addition the lungs dampen the "blood pressure spike".

brickeyee
September 9, 2011, 02:23 PM
Every few inches is a valve

ONLY in VEINS.

Arteries do not have them (or need them).

The valves in veins allow for random muscle movements that can compress the veins to aid the return flow of the blood to the heart.

The valves allow one way flow, back towards the heart.

Just as a point, folks who have heart bypass surgery are kept on stool softeners for a few days.
The force of trying to defaecate could cause the new joints in the cardiac arteries to blow out until they have started to knit and heal.

that's right, pushing to poop could cause enough additional pressure at the heart to blow the connections.

481
September 9, 2011, 02:35 PM
But they do flatten out and distort their shape vs. being supported in the body.

A water balloon would be a good example.
What percentage of the contents is water?
How does it behave when struck or force is applied?

Our tissue is overwhelmingly water, with cell membranes giving it some shape and form.

When it is struck, especially by fast moving objects like bullets, it behaves as a gel.

A material that is somewhere between a pure liquid and a solid.

Bones behave closer to a solid, but still contain marrow and pother cells that are NOT a solid (calcified).

Is cartilage a solid?

An excellent perspective on the topic, the best that I've read in a long time. :)

In his book, "Bullet Penetration", MacPherson treats calibrated 10% ordnance gelatin as a "soft solid" with a high viscosity (~150 Poise) since it's able to sustain shear forces whereas fluids cannot. For the purposes of such discussion, it is a description that seems to "hold water" (I couldn't resist the pun, sorry :p) very well for how the material behaves under projectile impact forces.

Vern Humphrey
September 9, 2011, 03:58 PM
When you shoot a handgun, how much energy is dumped in your palm? A similar amount of energy is dumped into the target (physics) and it isn't enough to make any difference. What counts is tissue destroyed along the path of the projectile, and that is not as simple as measuring kinetic energy.
What acts on your palm is momentum (Momentum = mass * Velocity.) Kinitic energy is calculated as Energy = mass * Velocity^2.

Loosedhorse
September 9, 2011, 05:10 PM
Vessels are not rigid pipes. They are elastic, which stretch and dampen the amplitude of the "blood pressure spike".Very good point. I think the response would be along the lines of a "high-pass" filter: that a system that is flexible enough to totally absorb a low energy (slow) deformation may transmit a higher energy wave pretty well. So that a blood vessel that flexes in response to a heartbeat may act fairly rigid during the brief transmission of a ballistic pressure wave.

The high-pass aspect doesn't change the fact that the energy would attenuate with distance; but it would not dampen as quickly.What acts on your palm is momentumI think both kinetic energy and momentum would be imparted from the gun to my palm, and from there distributed elsewhere.

Vern Humphrey
September 9, 2011, 05:29 PM
I think both kinetic energy and momentum would be imparted from the gun to my palm, and from there distributed elsewhere.
If that were true, your palm would suffer as much damage as the target.

two gun charlie
September 9, 2011, 05:47 PM
Well according to an article posted in a medical journal on neurosurgery the phenom of hydrostatic shock is well established.

Odd Job
September 9, 2011, 06:18 PM
The high-pass aspect doesn't change the fact that the energy would attenuate with distance; but it would not dampen as quickly.

And that one statement is what upsets and derails the ballistic pressure wave theory.

1) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave originating closer to the head (such as the root of the neck) must produce a more overt "insult" to the brain. Where is the evidence for this? I personally saw a case where an adult male had most of his face removed by a contact wound from a .303 (ammunition unknown). His CT scan was clear (intracranially) and his GCS was normal for a person who is intubated (airway protection). Not one tiny little bleed was seen in the brain, yet the face was removed from the angles of the mandible all the way up to the nasion.

2) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave must also apply the same "insult" to organs inferior to the chest, for example the kidneys. Where is the damage to the very fine vessels in the kidneys? Why is it we don't see haematuria (even microscopic) in patients who have sustained a GSW to the chest?

3) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then a greater ballistic pressure wave originating in the chest must produce a more overt "insult" to the brain. There should be overt and obvious findings of brain damage in individuals shot in the chest with rifle loads producing a greater ballistic pressure wave than handgun loads. Where are the reports (either from the ER or from the pathologist)?

This ballistic pressure wave theory has been touted by Michael Courtney on numerous boards over the years. He is the one who has altered/provided the most recent content in that Wiki also.
A few things to note (which I have posted on other boards also):

Over the years we have had many debates with Courtney, mainly on other boards.
When he first showed up on TacticalForums, everyone greeted him warmly and we were all receptive to his research.
It soon turned out that he was doing things backwards. He had arrived at a conclusion and was collecting disparate references to support it. What the pay-off would be if he got the theory accepted, I don't know for sure. It was one of two possibilities: either the ammunition or the treatment.
He could have wrapped this up years ago by submitting the heads of the shot deer for analysis by board certified veterinarians.
Every time I have made that suggestion he has come up with excuses...each one more ridiculous than the last.
First he said that he couldn't exclude head injuries on these deer from when they fell to the ground after being shot. I suggested a soft bait station but he said he isn't allowed to bait these. When asked about the veterinarian's input (or lack thereof) he claims financial limitations. He shies completely away from any kind of medical input whether it is expertise with animals or humans.
This is a guy with a PhD, doing a prospective research project. I recently completed a Master of Science degree in Health informatics and my final project was an expert system to do with the detection and enumeration of projectile fragments in humans from GSWs.
With these projects you have a proposal, a supervisor or advisor and a clear outline of what you are trying to do and what the acceptable measures of the outcomes will be. Even if he doesn't have to confirm to a university's work plan approval, his academic pedigree (which on paper is certainly higher than mine) should imbue his project with an element of academic integrity which needs an honest unbiased approach to the subject matter.
You don't on one hand claim that you cannot do the required testing on the deer because you will be hounded by PETA and then on the other hand announce that you have placed raccoons in buckets and fired into the water, resulting in the delayed death of at least one of those animals (again with no analysis by the required specialists to exclude pulmonary oedema or drowning as a cause of death).

I told him many moons back that I would accept his theory if he could show me one pair of deer that had been analysed post shooting (one by arrow, one by bullet), and there was definite evidence confirmed by an unbiased appropriate expert that the deer killed by bullet had neurological flags that the other one didn't. How hard is that to do, and is it really financially or academically taxing compared to the sum of all of his other efforts over the years related to this theory?

It wouldn't suit him to do it, because then his theory would be solidly rejected and he would get no foot in the door for whatever pay-off or commercial venture he envisages this BPW may unlock.

When I did my project, I provided a basic outline of what I was doing and also access to the associated online logic system I developed so that radiologists, trauma surgeons, AFTE, military and LEO persons could give me feedback and criticism on it. I used a database of 150 GSW patients where I had collected photographs of wounds, clothing, medical imaging and also operative and clinical notes and even photographs of recovered projectiles to do my study. I also had background statistics for the entire research period which encompassed an available sample of 542 patients. I collected this single-handeledly on site at a trauma unit in South Africa, with no funding and at the time with nothing more than a Diploma to my name.

Imagine how disappointed I was when I couldn't get the system to consistently match projectiles and trajectories in circumstances where a person may have more than three skin breaches.
Instead of trying to peddle this system (I have had a lot of interest in this work) I have had to back off because I can see that this isn't going to work. I may have to try something different, such as doing another project where I can get ethical clearance to change the way in which routine X-ray imaging is done for a prospective sample of GSW patients.
That is the correct thing to do.

Disparate references, meandering around available resources which could prove or refute his theory in short order, and dare I say it a certain lack of academic integrity and ethics on the part of Courtney have led me to take an adversarial stance against him.

Whilst I have seen traumatic effects one or two inches from a bullet's terminal trajectory in real patients in a variety of tissues, there is nothing in the totality of the evidence available to support Courtney's BPW theory and I for one don't buy it.
He published it in a journal, yes, but that doesn't mean it is sound. You can check the articles by Wakefield and the MMR scandal here in the UK if you want an example of less than forthright academic publishing.

Courtney scoured all the literature and all he could find was one gunshot face from the 40s, reported in the 90s IIRC, with a supposed link between that injury and a subsequent finding of epilepsy in that patient. I posted here on GT an exact reconstruction of the trajectory of that bullet based on the author's own information in the article and guess what I found in the path of that bullet: vertebral arteries. It is disengengious for Courtney to even cite that reference because there was no computed tomography in the 40s when the injury was acutely treated, and there was no digital subtraction angiography either. It is further compounded by his apparent disdain for other peoples' offering of Vietnam-era data where he claims the imaging and diagnostic techniques were not sophisticated enough to detect BPW effects. When it suits him, the imaging and clinical data is enough, when it doesn't suit him not only does he claim we aren't doing enough to detect this, but he offers no prospective study of his own to confirm it.

And here is the recon:

http://i55.photobucket.com/albums/g154/Odd_Job/MIP.jpg

This is my summary of the state of play at present:

At this point the BPW theory is academic, Courtney has moved on. Whatever pay-off he envisaged getting once he got the theory accepted in the domain is clearly unattainable now. The institutions/agencies that would have been necessary to have buy-in obviously didn't go for it and Courtney has moved on to other things.

We all agree in principle to use a service calibre weapon with reputable expanding ammunition with the potential to penetrate to the vitals. If you believe that ammuniton X satisfies that and also provides a certain percentage/probability of causing incapacitation by remote neural/vascular damage, then go for it and get that. Everything else is just wasted bleating.

If you want to see the whole gory thread, it is on GT:
http://glocktalk.com/forums/showthread.php?t=1346952&page=11

Strykervet
September 9, 2011, 06:34 PM
Are there no trauma surgeon/gun enthusiasts on here that can put this to rest once and for all?

I've read stuff from a morgue worker and he said that rifle fire was almost always lethal and almost always killed in one round. Now correct me if I'm wrong, but a 7.62 is smaller diameter than a 9mm, but both flavors in FMJ will over penetrate.

Then the 9mm should be better than the 7.62. But it isn't.

He said that rifle victims were rare, but were almost always instantly lethal. He said that a 7mmMag victim had liquified organs. Massive trauma. Most rifle and shotgun wounds he saw were head shots, suicides. But the few that came through with COM shots were nasty.

He also noted that 9mm victims came in with several shots. Usually .40 and .45 were one or two shots. Obviously whoever was firing didn't feel the 9mm was putting them down fast enough.

So it would seem for pistols, that bigger is better. For rifles, faster is better. I think this arguement has become a cycle, I've been interested in this kind of thing since I first started shooting when I was 8yo. I've read about it until the internet came along, then discussed it. We're still where we were 20 or 30 or more years ago.

That really is the bottom line. Until we get a trauma surgeon on here to set us straight, it'll just have to be a little mysterious yet.

Derek Zeanah
September 9, 2011, 08:20 PM
I can't offer anything but a second-hand anecdotal account, but it sounds like that's what you're looking for: when the wife was in med school, she had one week where she had one patient who had been shot with a 12ga shotgun, and another that had been shot with an "AK47" (so figure an SKS or something.)

Her assessment at the time: she'd rather take the close-range buckshot then the rifle round. In the end the rifle victim had to keep going back through surgery to have additional tissue removed, with the end result of it being a more devastating wound.

Anecdotal, and completely dependent on my memory (I asked her and the events in question have all blended together with the rest of the crap she saw in training), but I was convinced.

Loosedhorse
September 9, 2011, 09:03 PM
Appreciate the perspective, Odd Job. Good stuff to chew on. Most of the response would I think again center on concussion: that loss of consciousness can at times be observed (with direct blunt trauma to the skull) even without cerebral contusion or other clear signs of injury (other than changes in the concentrations of some neurotransmitters and some inflammation mediators).

It remains the case that, even if pressure-wave-induced unconsciousness occurs, it seems to be an undependable phenomenon.

(Oh--and I always thought Odd Job was the best Bond henchman. Way better than Jaws. :))

Decembeard
September 9, 2011, 09:34 PM
Can you not think of it like this?
Take fire cracker and ignite it on the ground or empty can. Small damage.
Put that same fire cracker in a can full of water and you have a lot more damage and force given off.
moot point. This is not a description of hydrostatic shock. The gases caused by the rapid conflagration of the firecracker simply displace the water. Since water cannot be compressed, it has to move out of the way. This is why it ruptures the can. As for more force given off, that's simply impossible. The same type of firecracker will give off approximately the same force. It draws no other strength from the water it's in.

THplanes
September 9, 2011, 11:17 PM
.I think both kinetic energy and momentum would be imparted from the gun to my palm, and from there distributed elsewhere.

If that were true, your palm would suffer as much damage as the target.

The bullet and the gun have about the same momentum. The momentum of the gun will be a little higher because of the momentum of the powder gasses that act primarily on the gun.

K.E. is a totally different situation. Since it's based on velocity squared, the bullet has much more energy than the gun. In the earlier post with the .357 mag example the velocity and K.E. numbers are:

2 lb .357 mag at 17.25 fps = 9 ft-lbs
158 gr bullet at 1250 fps = 548 ft-lbs



The K.E. of the gun is also distributed over the surface of your hand in contact with the gun. The K.E. of the bullet is distributed over a much smaller area.

THplanes
September 9, 2011, 11:51 PM
Vessels are not rigid pipes. They are elastic, which stretch and dampen the amplitude of the "blood pressure spike". They are also connected to other vessels, which disperse and dissipate the "blood pressure spike". In addition the lungs dampen the "blood pressure spike".

You can't talk about blood vessels as if they are all the same. Veins are low pressure and have valves. Arteries are high pressure and don't have valves. Arteries are designed to move blood efficiently. They're not designed to dampen BP. If you hold your upper arm and wrist at the same level, there will be very little difference in BP.

The lungs dampen the transmision of the pressure produced by the TSC to the major vessels in the chest. Once the BP spike occurs the lung do nothing to dampen it.



I have a few questions for the Fackler camp that I can't any other Facklerite to answer, so I'll try you.

1) Are there any lab animal studies that show shots in the extremities show an increase in intra-cranial pressure. For those that don't know, BPW's proposed mechanism is by increase in intra-cranial pressure.

This is really a rhetorical question. There is a study done on anesthetized dogs shot in the thigh that demonstrates this to be a fact. There are also at least 2 other studies that show an increase in pressure at a location remote from the wound site. That BPW exists is a fact. Since these studies were done on anesthetized animals, the question of at what, if any, point does the pressure increase hinder an individuals ability to function is left open.

2) Fackler holds the view that any rapid incapacitation can only occur by
a) CNS damage
b) psychological incapacitation.

The question is, where are the psychological studies that back this up.

3) Fackler seems to make the claim that psychological incapacitation is independent of caliber, at least within the realm of service pistol calibers. Doesn't matter if it's a FMJ 9mm or a 125 gr SJHP .357 mag.

Where are the psychological studies that back this up.

THplanes
September 10, 2011, 01:02 AM
The high-pass aspect doesn't change the fact that the energy would attenuate with distance; but it would not dampen as quickly.

And that one statement is what upsets and derails the ballistic pressure wave theory.

How?


1) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave originating closer to the head (such as the root of the neck) must produce a more overt "insult" to the brain. Where is the evidence for this? I personally saw a case where an adult male had most of his face removed by a contact wound from a .303 (ammunition unknown). His CT scan was clear (intracranially) and his GCS was normal for a person who is intubated (airway protection). Not one tiny little bleed was seen in the brain, yet the face was removed from the angles of the mandible all the way up to the nasion.

There are no large diameter blood vessels in the neck. The large blood vessels are in the chest. It's similar to this. If you take a 1/8" inch hose and rapidly collapse 3" of it, what happens to the pressure in the rest of the hose. On the other hand, what happens if you take a 1"x 3" tube with a valve on one end, 1/8 hose on the other and collapse a 3" section of the 1" hose. The volume of the tube being compressed makes a big difference.


2) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave must also apply the same "insult" to organs inferior to the chest, for example the kidneys. Where is the damage to the very fine vessels in the kidneys? Why is it we don't see haematuria (even microscopic) in patients who have sustained a GSW to the chest?

Are all forms of mild traumatic brain injury detectable by X-ray or CT. Do you need to see hematuria in order to diagnose mild TBA.


3) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then a greater ballistic pressure wave originating in the chest must produce a more overt "insult" to the brain. There should be overt and obvious findings of brain damage in individuals shot in the chest with rifle loads producing a greater ballistic pressure wave than handgun loads. Where are the reports (either from the ER or from the pathologist)?


Since there is a limited volume of blood in in the major vessels in the chest, this limits how much pressure change can occur. It's not an unlimited change in pressure, it's limited by the volume of the major blood vessels.

Second, you don't find what you're not looking for.

http://is.muni.cz/th/132384/lf_d/?furl=%2Fth%2F132384%2Flf_d%2F;lang=en

THplanes
September 10, 2011, 01:25 AM
Appreciate the perspective, Odd Job. Good stuff to chew on. Most of the response would I think again center on concussion: that loss of consciousness can at times be observed (with direct blunt trauma to the skull) even without cerebral contusion or other clear signs of injury (other than changes in the concentrations of some neurotransmitters and some inflammation mediators).

It remains the case that, even if pressure-wave-induced unconsciousness occurs, it seems to be an undependable phenomenon.


Yes it's unreliable, there are a number of factors that probably change how effective it is. Here are few obvious candidates:

Stomach and intestinal contents
Percentage of lung inflation
Where your actual BP is on the systolic-diastolic curve
Loss of elasticity of arteries
Some people just not susceptible to it ( I've seen people you'd swear a 2 year old could KO. I've seen others that the incredible hulk could take a telephone pole and knock them 2 blocks and they would come back and plant that pole in a dark place.)

This is why you'll find most people that believe BPW has an effect, including Dr. Courtney, advocate choosing loads that will get whatever level of penetration makes you happy first. Choosing a round with a high BPW is a secondary consideration.

You don't need to render your opponent unconscious to gain an advantage over them. Something as simple as mild confusion may hinder their ability to fire accurately and fast.

armsmaster270
September 10, 2011, 01:34 AM
Instead of all the formulas try this Click on picture to start

http://i239.photobucket.com/albums/ff207/armsmaster270/th_BallisticEffects.jpg (http://s239.photobucket.com/albums/ff207/armsmaster270/?action=view&current=BallisticEffects.mp4)

JohnKSa
September 10, 2011, 01:49 AM
If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave originating closer to the head (such as the root of the neck) must produce a more overt "insult" to the brain.I don't believe that necessarily follows.

In order for the ballistic pressure wave to form and propagate, the energy from the projectile must be coupled into the body. If the structures in the neck don't lend themselves particularly well to this type of coupling effect by which the energy from the projectile is transformed into a pressure wave, but the structures of the chest or trunk do, then it could be reasonable for a bullet striking the trunk to create more of a ballistic pressure wave effect in the brain than one striking the neck.

Odd Job
September 10, 2011, 06:19 AM
THPlanes says

There are no large diameter blood vessels in the neck. The large blood vessels are in the chest. It's similar to this. If you take a 1/8" inch hose and rapidly collapse 3" of it, what happens to the pressure in the rest of the hose. On the other hand, what happens if you take a 1"x 3" tube with a valve on one end, 1/8 hose on the other and collapse a 3" section of the 1" hose. The volume of the tube being compressed makes a big difference.

Carotid arteries x 2 and vertebral arteries x 2 are not enough? Have you checked the diameter of those and factored in that there are four of these vessels? It seems Michael Courtney himself would disagree with you about the value of those vessels: the aforementioned maxilla and neck injury in the Treib paper he cited was in Zone 3 of the neck. Too bad he didn't get the trajectory checked though.
If those neck vessels aren't good enough, I suggest you find whatever large vessel you are thinking of (in the chest) and trace it from point of impact to all its branches. If you compress the ascending aorta you cannot expect that displaced blood to act only superiorly and only in the brain. There are many branches on that aorta!

JohnKSa says:

In order for the ballistic pressure wave to form and propagate, the energy from the projectile must be coupled into the body. If the structures in the neck don't lend themselves particularly well to this type of coupling effect by which the energy from the projectile is transformed into a pressure wave, but the structures of the chest or trunk do, then it could be reasonable for a bullet striking the trunk to create more of a ballistic pressure wave effect in the brain than one striking the neck.

That's a slight deflection: do you subscribe to the notion that the vessels are the conduit for this pressure wave or not? Difficult to discuss your point otherwise.

THPlanes asks:

Are all forms of mild traumatic brain injury detectable by X-ray or CT. Do you need to see hematuria in order to diagnose mild TBA.

This is a side-step.
My comment was about the propogation of this ballistic pressure wave in all directions. If we are to entertain a theory that relies on the transmission of a wave through the vessels from the chest to the brain, we have to also ask where the effects of that wave are seen inferiorly. Where is the damage to the fine nephrons of the kidney (whose position and access in vascular terms would be more ideal candidates for damage via your pipe analogy than the brain)?


THPlanes says:

Since there is a limited volume of blood in in the major vessels in the chest, this limits how much pressure change can occur. It's not an unlimited change in pressure, it's limited by the volume of the major blood vessels.

Well, that's convenient, isn't it (if you actually believe it). I don't buy it, but I appreciate the value of that arguemnt as a loophole when the facts encountered in the ER get in the way. I can just see it now:

"The subject was too small to have sufficent blood volume for this wave to produce the effect"

or

"This was a borderline case where the effect was not seen because the shot happened in diastolic cycle."

THPlanes says:

Second, you don't find what you're not looking for.

http://is.muni.cz/th/132384/lf_d/?fu...f_d%2F;lang=en

It is you who don't look. Here is my comment on that link in the GT thread I referenced (I think you knew about that thread anyway because you POSTED in it):

That is a draft student paper. I emailed the author requesting a discussion with him about the histology slides where he claims to have micro-haemorrhages in the tissues from the GSW cases but not from the stabbings. He did not respond. I also went out of my way to line up a pathologist to discuss those slides (because I don't know anything about neuro-histology). I can't get hold of that student to debate his project, which is a pity because I think there are confounding variables in his study relating to the treatment and handling of those persons prior to and after their deaths respectively.

Loosedhorse
September 10, 2011, 07:53 AM
K.E. is a totally different situation. Since it's based on velocity squared, the bullet has much more energy than the gun.Thanks, TH. I did cover that in post #31 (and others did elsewhere), but I think your answer is particularly clear. Sometimes it helps to see the same info presented different ways, and so maybe now we've finally disspelled the "If that were true, your palm would suffer as much damage as the target" nonsense.

Separately, the idea that compressing a larger--aorta--vessel should produce more cerebral effect that collapsing a smaller--carotid--one hadn't occured to me, because I didn't consider collapse of large vessels as occuring in response to a BPW. It prompts the question: do we know that radial compression of the aorta is how ballistic pressure waves are produced?

JohnKSa, the idea of optimal energy coupling is important, too.

It's a nice discussion, folks--thanks!

THplanes
September 10, 2011, 08:20 AM
.
Separately, the idea that compressing a larger--aorta--vessel should produce more cerebral effect that collapsing a smaller--carotid--one hadn't occured to me, because I didn't consider collapse of large vessels as occuring in response to a BPW. It prompts the question: do we know that radial compression of the aorta is how ballistic pressure waves are produced?

JohnKSa, the idea of optimal energy coupling is important, too.

It's a nice discussion, folks--thanks!

No, we don't know that for sure. Most of the ideas about the mechanism are more theory than anything else. We do know factually that dogs shot in the thigh show an increase in intra-cranial pressure. That's really about all we know as hard factual data.

I had a response to Odd Job just about done and it timed out one me. I'll redo it later today.

MachIVshooter
September 10, 2011, 09:35 AM
We do know factually that dogs shot in the thigh show an increase in intra-cranial pressure.

I'd like to see the rest of the vitals that went along with that. General anesthesia does not render the parasympaythetic nervous system non functional, so the increased BP and cranial pressure could have been caused by increased heart rate with adrenal response to the injury.

As well, I don't think any of us are arguing that bullets passing through bodies create pressure, just that it isn't a wounding mechanism. Sneezing (among other less pleasant bodily functions) also increase pressures, but unless a person is medically compromised in other ways, these normal body functions don't cause a crippling disruption of the nervous system.

Loosedhorse
September 10, 2011, 11:28 AM
General anesthesia does not render the parasympaythetic nervous system non functional, so the increased BP and cranial pressure could have been caused by increased heart rate with adrenal response to the injury.General anesthesia suppresses brainstem function, which is why an artificial respirator must be employed. So, general anesthesia would prevent a brainstem-mediated general (endocrine) release of adrenaline into the blood, or other brainstem-mediated changes in blood pressure.

The intracrainial pressure rise that was talked about in the dog experiment is, I believe, transient, beginning and ending with the passage of the bullet. Endocrine and brainstem-mediated changes in BP cannot begin and end that fast.

Atropine, a parasympathic blocker, is typically given during general anesthesia--I do not know if it was given in this case. The release of adrenaline into the blood is actually part of the sympathetic system; there are also sympathetic blocking agents widely available, though again I do not know if they were employed.Sneezing (among other less pleasant bodily functions) also increase pressures,There is extensive literature on sneeze syncope, cough syncope, weight-lifter syncope, brass-player syncope, etc. As you say, they affect just a few people.

A typical cough generates up to 5 psi of transient pressure in the thorax. The Coutneys specify 1000 psi as their BSW entry level. We might suppose that if a few patients are affected by a 5 psi transient, then many more would be affected by one 200 times greater.

brickeyee
September 10, 2011, 11:28 AM
The same type of firecracker will give off approximately the same force. It draws no other strength from the water it's in.

The water is very efficient at transferring movement and energy.

While tha can full of air may contain the blast, a can full of water may burst.

Even shot at cans full of water?

Even a .22 RF can often manage to split the thin aluminum.

An empty can may not even move when hit sometimes.

A shot a beer can full of water once at 100 yards with a .30-06 with a 150 gr bullet.

It made an instant cloud of fog.
The can was blown into shreds, with the bottom formed and sticking to the rock the can was sitting on.

Empty cans just go flying.

Cop Bob
September 10, 2011, 12:11 PM
I think that what has taken place in this thread is basically a whizzing contest over the DEGREE or AMOUNT of hydraulic shock, or hydraulic energy transfer..

Agreed, Rifles do far more TISSUE damage as a result of HYDRAULIC SHOCK because of the combination of weight and speed, and penetration..

Handguns have far less CATASTROPHIC TISSUE DAMAGE because they lack the speed required to produce the larger shock wave that high velocity rifle rounds do..

But BOTH produce a HYDRAULIC EFFECT WITHIN A BODY...

Where folks seem to be argueing is on the DEGREE or AMOUNT of hydraulic shock that is transfered or delivered..

Understand, that in a SD handgun round, we are looking for sufficient energy transfer to cause an IMMEDIATE disruption to the CNS to cause a a rapid, or immediate incapacitation.. Temporary of permanent, we will take either.. as long as it ends the fight quickly and to our advantage.. Unfortunately, to effectively do this with any hope of reliable and predictable desired effects, round or shot placement is critical... and to insure the desired effect, the rounds must me aimed at areas that also will result in death.. Center mass, or "the Fatal T".

While veins and arteries are conduits for blood, (fluid) throughout the body, the body is approximately 86% water. COmposed of blood, bile, and a host of other aqueous compounds, all that will act to transfer energy to a varying degree. the amount of fluid moving through the vascular system as a result of a bullet impact would be minuscule in relation to the wave that is moving through the body via the flesh and organs.. I think that we can all agree that abdominal areas are more aqueous than muscle, and that the facial area is loaded with sinus cavities that are mostly air, and therefore compressive and less likely to transfer hydraulic force.

This could explain why a rifle round across the front of the face would not destructively disrupt the brain.. I too have seen similar effect in a shooting victim with a 30-30, his brother managed to blow his lower jaw off, along with most of his tongue, and a few teeth out of the upper mouth, but he was alert conscious and oriented in the ER.. He was able to write us as to how stupid they were... I wish a had kept some of those pictures. Lower jaw area, bone, muscle and air.. little to transfer energy... But man it looked like it hurt!

It does not take a huge, flesh tearing, explosive force to render a person unconscious, or to cause their central nervous system to temporarily short circuit.. If would be interesting to see an EKG and an EEG of an individual at moment of impact of rounds of various types and placement.. but I would bet that the universal trait would be the EEG would go off the charts... The only question would be how far off the charts and for how long..

I think that everyone here agrees, that a hit from a 9mm is nowhere near as bad as a hit in the same spot from a 7 mag.. and I think that we all agree that a head shot with a 158gr 38, would not be near as "graphic" as a head shot from a 168 gr .308.. but the victim would be just as dead... for you see, as many bodies as I have viewed in my lifetime, I have never seen varying degrees of dead... it is only a matter of how fast they got there.. dead is dead...

However not everyone, or thing that absorbs the impact of a bullet, goes down immediately, that is just not the real world.. So what we all seek, is a round that will take as much ability to fight, or take flight in the case of game, as possible... This is done, in handguns, through the use of good hollow point ammunition, pushed as quickly as it can safely be... or in the case of rifles, with Soft Point or other expanding ammunition.. We seek antiquate penetration so that the maximum transfer of energy takes place along the entire length of the deepest wound track we can generate, and ideally not exiting the body, for both the maximum effectiveness of the round via energy transfer, and the liability reasons of the possibility of collateral damage.. This is why we chose different bullet weights for different game, or applications..

I think that we would all agree, that ether we are hunting or going into a combat situation, that we would be loading with the best rapid expanding handgun ammunition, or SP, or ballistic tip rifle ammunition we could get our hands on.. Why, because we want that, however tiny or catastrophic it may be, edge of hydraulic forces working for us...

But I too, am still looking for that .22 or 32 caliber pistol round that has no recoil, cannot miss, and has the terminal ballistics of a harpoon missile.. when they come out with that, somebody left me know.. I want two!

MachIVshooter
September 10, 2011, 12:40 PM
General anesthesia suppresses brainstem function, which is why an artificial respirator must be employed. So, general anesthesia would prevent a brainstem-mediated general (endocrine) release of adrenaline into the blood, or other brainstem-mediated changes in blood pressure.


Brainstem controls much of our involuntary function, reaction and reflex-but not all, and some of those functions can be/are controlled by the Vegas nerve in the absence of spinal cord function. There are also many people who experience varying levels of consciousness during sedation from general anesthesia. The nervous system is really very little understood.

brickeyee
September 10, 2011, 02:05 PM
There are also many people who experience varying levels of consciousness during sedation from general anesthesia.

They have not been given enough.

It is a real problem sometimes.

Even with supported respiration (patient on a ventilator) the ling between anesthetized and dead is very fine.

481
September 10, 2011, 03:09 PM
And that one statement is what upsets and derails the ballistic pressure wave theory.

1) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave originating closer to the head (such as the root of the neck) must produce a more overt "insult" to the brain. Where is the evidence for this? I personally saw a case where an adult male had most of his face removed by a contact wound from a .303 (ammunition unknown). His CT scan was clear (intracranially) and his GCS was normal for a person who is intubated (airway protection). Not one tiny little bleed was seen in the brain, yet the face was removed from the angles of the mandible all the way up to the nasion.

2) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then the same ballistic pressure wave must also apply the same "insult" to organs inferior to the chest, for example the kidneys. Where is the damage to the very fine vessels in the kidneys? Why is it we don't see haematuria (even microscopic) in patients who have sustained a GSW to the chest?

3) If a ballistic pressure wave originating in the chest is responsible for an "insult" of a certain magnitude being applied to the brain, then a greater ballistic pressure wave originating in the chest must produce a more overt "insult" to the brain. There should be overt and obvious findings of brain damage in individuals shot in the chest with rifle loads producing a greater ballistic pressure wave than handgun loads. Where are the reports (either from the ER or from the pathologist)?

This ballistic pressure wave theory has been touted by Michael Courtney on numerous boards over the years. He is the one who has altered/provided the most recent content in that Wiki also.
A few things to note (which I have posted on other boards also):





And here is the recon:

http://i55.photobucket.com/albums/g154/Odd_Job/MIP.jpg

This is my summary of the state of play at present:



If you want to see the whole gory thread, it is on GT:
http://glocktalk.com/forums/showthread.php?t=1346952&page=11

Odd Job,

An excellent and broadly comprehensive perspective. Your posts always make my head hurt (in a good way :D ) and the information you've passed on is an education in itself.

Thanks.

Odd Job
September 10, 2011, 03:11 PM
As well, I don't think any of us are arguing that bullets passing through bodies create pressure, just that it isn't a wounding mechanism. Sneezing (among other less pleasant bodily functions) also increase pressures, but unless a person is medically compromised in other ways, these normal body functions don't cause a crippling disruption of the nervous system.

That's it, exactly!

On a similar note, I can say with certainly that there IS damage to tissues that are not in the direct path of the bullet in certain circumstances. I have seen it myself in only a handful of cases...BUT in all instances the damage has been within an inch or two of the bullet track.

The best case I saw was a gunshot liver that resulted in a spectacular stellate tear of the liver capsule and marked cavitation of the liver tissue beyond the size of the bullet. That can be partly explained by temporary cavity exceeding the limits of the liver's ability to yield. It is not elastic.

In another case I saw a subclavian artery intimal flap from a posterior to anterior GSW of the upper chest. There were multiple fractured ribs also, these were in the path of the bullet but the subclavian artery was not (although it was close). The intimal flap was found by angiogram after radial pulses were not equal when comparing right to left.

In the case of the liver injury you could argue that the cavitation contributed to the severity of the wound, but in the case of the intimal flap this is not the case.
There have been documented cases of fractures to delicate orbital plates from intracranial GSWs but that is to be expected if you have an enclosed space where there is no pressure release. So those are a special case.

Malcolm Dodd has published a nice atlas on gunshot wounds, it is called Terminal Ballistics and it can be bought online:

http://www.amazon.com/Terminal-Ballistics-Atlas-Gunshot-Wounds/dp/0849335779

Some very useful info in there, I bought my copy some time ago.

brickeyee
September 10, 2011, 03:58 PM
As well, I don't think any of us are arguing that bullets passing through bodies create pressure, just that it isn't a wounding mechanism. Sneezing (among other less pleasant bodily functions) also increase pressures, but unless a person is medically compromised in other ways, these normal body functions don't cause a crippling disruption of the nervous system.

The body knows how to cope with them, bullets, not so much.

gamestalker
September 10, 2011, 07:34 PM
Hydro static shock if no myth. I've killed a lot of big and small game with high powerd rifles and the type of damage created by liquids not being able to disperse is daunting. I once shot a coyote with a .270 hand loaded 90 gr. HP and the coyote litterally exploded into the the under side of the tree he was standing under. No exageration here, that dog was litterally unrecognizable and completely disenegrated. And jack rabbits, well just let me say that there is no more than fur and blood left.

JohnKSa
September 10, 2011, 10:27 PM
That's a slight deflection: do you subscribe to the notion that the vessels are the conduit for this pressure wave or not? Difficult to discuss your point otherwise.It's not a deflection at all.

Wires are excellent conduits of electricity, but wires don't necessarily make good antennas unless they're specially constructed to couple well to radio waves. In a similar fashion while the blood vessels in the neck might be reasonably good at conducting the pressure waves from the torso to the brain, it might be difficult to couple the pressure waves directly into them via an impact to the neck.

In other words, the torso has a lot of tissue types (and a lot of tissue) not found in the neck. Those tissues and tissue types might be required to couple the pressure wave from the bullet into the blood vessels. Once the pressure wave is coupled into the blood vessels they could act as the conduits to move it to other parts of the body.

The neck is a structure mostly composed of bone, blood vessels, muscle and connective tissue. It seems somewhat reasonable to assume that the torso, a region filled with a lot of fluids and soft tissues, might couple bullet energy more effectively into blood vessels.

I'm not trying to rigorously defend a theory here, I just think it's worth pointing out that coupling the energy into the vessels in the first place probably requires more than just having a bullet pass close by. It might require having a bullet pass close to a vessel that's surrounded by certain types of soft tissue that allow the energy of the projectile's passage to be readily transferred to the blood vessels.

All of that to say, I don't think it necessarily follows that a bullet strike to the neck would automatically create a more significant pressure wave incident in the brain than a bullet strike to the torso.

Mike1234567
September 10, 2011, 10:38 PM
* deleted *

Odd Job
September 11, 2011, 05:23 AM
JohnKSa says:

Wires are excellent conduits of electricity, but wires don't necessarily make good antennas unless they're specially constructed to couple well to radio waves. In a similar fashion while the blood vessels in the neck might be reasonably good at conducting the pressure waves from the torso to the brain, it might be difficult to couple the pressure waves directly into them via an impact to the neck.

In other words, the torso has a lot of tissue types (and a lot of tissue) not found in the neck. Those tissues and tissue types might be required to couple the pressure wave from the bullet into the blood vessels. Once the pressure wave is coupled into the blood vessels they could act as the conduits to move it to other parts of the body.

The neck is a structure mostly composed of bone, blood vessels, muscle and connective tissue. It seems somewhat reasonable to assume that the torso, a region filled with a lot of fluids and soft tissues, might couple bullet energy more effectively into blood vessels.

I'm not trying to rigorously defend a theory here, I just think it's worth pointing out that coupling the energy into the vessels in the first place probably requires more than just having a bullet pass close by. It might require having a bullet pass close to a vessel that's surrounded by certain types of soft tissue that allow the energy of the projectile's passage to be readily transferred to the blood vessels.

All of that to say, I don't think it necessarily follows that a bullet strike to the neck would automatically create a more significant pressure wave incident in the brain than a bullet strike to the torso.

That's an interesting theory. The dependance of tissue types or the presence of different tissue types can hurt the theory also. In the torso the lungs won't be a good material for the propagation of a pressure wave because of air spaces in the alveoli. The shot then has to be confined to the mediastinum below the level of the apex of the arch of the aorta. You may as well confine it directly to the heart and major vessel roots if that is the case.

Another way to get at the answer then is to ignore the head and look only at the abdomen. If a ballistic pressure wave from the chest can affect the brain, then it must also affect the abdomen, specifically I am interested in the kidneys.
If that shot is then compared to a sub-diaphragmatic shot, then we should expect to see more overt features of fine vessel damage in the kidneys or maybe even the liver (assuming no direct hits of either, to confound the issue) from the shot to the upper abdomen.

I just haven't seen it.

I have to go by what I and my colleagues have seen up close in the ER over the years. All those trauma patients get a micro urinalysis. I would be expecting two features then:

1) A significant number of positive haematuria cases from GSWs to the chest (with no other aetiology).
2) A significant and greater number of haematuria cases from GSWs to the abdomen (with no other aetiology and no direct strike to the urinary tract).

Somebody needs to show me the evidence for that, because I haven't seen it and I have seen several thousand GSWs in person. Not journal cases from the 1940s, but real acute cases in the ER.

brickeyee
September 11, 2011, 09:17 AM
Wires are excellent conduits of electricity, but wires don't necessarily make good antennas unless they're specially constructed to couple well to radio waves.

But ANY wire couples SOME energy in an RF field.

Efficiency is not the issue here.

The ability to couple AT ALL is the issue.

Loosedhorse
September 11, 2011, 09:42 AM
Brainstem controls much of our involuntary function, reaction and reflex-but not all, and some of those functions can be/are controlled by the Vegas nerve in the absence of spinal cord function.The vagus nerve originates in the brainstem, so anything that suppresses the brainstem will suppress the vagus nerve. The list of its functions is easily found. Yes, since the vagus is not in the spinal cord, it can function in the absence of a spinal cord--although such a patient will not be able to breath without spinal cord function!There are also many people who experience varying levels of consciousness during sedation from general anesthesia.As has been said, only if they are not really under general anesthesia at that moment. There is no consciousness when actually under general anesthesia.The nervous system is really very little understood. There are many remaining mysteries about the nervous system; I already mentioned the questions regarding concussion syndromes. However, what any one person thinks is "not understood" about the CNS might more reflect what he doesn't understand than what is actually not understood. Further: any mysteries go more toward causing us to consider novel theories of incapacitation, as we do not have sufficient knowledge to exclude them.

Finally, what does any of your comment have to do with arguing against the BSW theory? I begin to wonder if you are just making inaccurate human physiology statements on purpose, to taunt me into correcting them? (Vegas nerve, indeed! :rolleyes: Have you no shame?)
I have to go by what I and my colleagues have seen up close in the ER over the years. All those trauma patients get a micro urinalysis.Are the Courtneys alleging microhemorrhage in the CNS as a result of BSW? If they are not, then why would we expect microhematuria? Even if they are, it could be argued that the structure of the kidney (including its vasculature) is enough different from the CNS that a BSW produces microbleeds in one system, but not the other.

So, either way, I'm not sure on why I should consider the kidneys as being able to disprove the BSW theory.

Odd Job
September 11, 2011, 10:23 AM
Are the Courtneys alleging microhemorrhage in the CNS as a result of BSW?

Yes he did. He proudly referenced the student Czech paper for that purpose.

Even if they are, it could be argued that the structure of the kidney (including its vasculature) is enough different from the CNS that a BSW produces microbleeds in one system, but not the other.

We have no evidence of either case producing micro bleeds, so I guess if it comes to a comparison like that which seeks a definitive answer, the proponent of the theory will just have to do some tests/experiments to prove it. The onus isn't on me to disprove it, it is on him to prove it. He could have done it a long time ago with animal experiments but elected not to. Obviously an element of mystery is more commercially viable than outright failure.

So, either way, I'm not sure on why I should consider the kidneys as being able to disprove the BSW theory.

Because they are delicate organs with very fine vasculature and unimpeded arterial access. If people can frequently have haematuria after extra-corporeal shockwave lithotripsy then I don't see why they can't have that from a ballistic pressure wave.

Loosedhorse
September 11, 2011, 03:24 PM
If people can frequently have haematuria after extra-corporeal shockwave lithotripsy then I don't see why they can't have that from a ballistic pressure wave.What? Why in the world would it be surprising that ESWL produces hematuria? And why would BSW be at all simliar to ESWL.

People undergoing ESWL already have renal lithiasis: crystaline stones in the calices or ureter--good reason for hematuria already! A total of perhaps 2000 shockwaves are delivered with a total energy of perhaps 150 Joules (both figures are sometimes exceeded). That's about 110 ft-lbs, delivered to a focal volume as small as 450 cubic mm. If successful the lithotripsy breaks the calculus so that the pieces (and their sharp edges) pass through to the bladder, we have more reasons for blood in the urine. If slightly misaligned, the energy is not delivered to the stone, but to the adjacent renal structures.

So why shouldn't there be bleeding? Heck, there are sometimes renal hematomas after ESWL! But why should we presume ESWL is anything like BSW? My guess is if you focused ESWL enrgy at the surface of the brain, you could produce red blood cells in the CSF--but so what?

One thing that ESWL does teach us about the theory of BSW? ESWL is only possible because shockwaves propagate through the human body with minimal loss of energy; that seems to be a mark against the idea that the shockwave is "dampened" as it passes through tissue.

(If I have perhaps misunderstood, and you mean that ESWL of gallstones routinely leads to hematuria, then I apologize for my foolishness. If I have not misunderstood, then perhaps I must pass the fool's cap along...;))He proudly referenced the student Czech paper for that purpose.Ah. Thanks.

Shawn Dodson
September 11, 2011, 04:58 PM
Ballistic Pressure Wave? - http://www.firearmstactical.com/images/gymnast.mpg

Ballistic Pressure Wave? - http://www.youtube.com/watch?v=r8eKyKQPgt0&oref=http%3A%2F%2Fwww.m4carbine.net%2Fshowthread.php%3Ft%3D34407%26page%3D2

Eb1
September 11, 2011, 05:27 PM
All of those shots were poor shot placement on the animal IMO. The heart is lower on a pig. Also that is why you shoot a pig in the ear.

JohnKSa
September 11, 2011, 05:53 PM
The dependance of tissue types or the presence of different tissue types can hurt the theory also. In the torso the lungs won't be a good material for the propagation of a pressure wave because of air spaces in the alveoli.That seems a logical extension of the assumptions. And it doesn't hurt the theory, it actually provides a possible explanation of why the effect isn't seen reliably even with solid torso hits. You would have to hit an area with a large blood vessel surrounded by a certain type of tissue in order to have a chance of seeing the effect. Hit an area with the right type of tissue but no large blood vessel--no significant effect. Hit an area with a large blood vessel but not enough of the right type of tissue--no significant effect.The shot then has to be confined to the mediastinum below the level of the apex of the arch of the aorta. You may as well confine it directly to the heart and major vessel roots if that is the case.There are a lot of very large blood vessels that run through the abdomen, and lots of fluid-filled tissues there as well.But ANY wire couples SOME energy in an RF field.

Efficiency is not the issue here.

The ability to couple AT ALL is the issue.No, both would be important. The question was why a torso hit would cause an effect in the brain while a neck hit didn't show a stronger effect. If the neck doesn't have the kind of tissues that couple projectile energy into blood vessels very well then that lack of coupling efficiency could mean that a hit in the neck might result in a weaker effect to the brain even though it's closer to the brain than the torso.

Odd Job
September 11, 2011, 05:58 PM
LoosedHorse says

What? Why in the world would it be surprising that ESWL produces hematuria? And why would BSW be at all simliar to ESWL.

People undergoing ESWL already have renal lithiasis: crystaline stones in the calices or ureter--good reason for hematuria already! A total of perhaps 2000 shockwaves are delivered with a total energy of perhaps 150 Joules (both figures are sometimes exceeded). That's about 110 ft-lbs, delivered to a focal volume as small as 450 cubic mm. If successful the lithotripsy breaks the calculus so that the pieces (and their sharp edges) pass through to the bladder. If slightly misaligned, the energy is not delivered to the stone, but to the adjacent renal structure.

So why shouldn't there be bleeding? Heck, there are sometimes renal hematomas after ESWL! But why should we presume ESWL is anything like BSW? My guess is if you focused ESWL enrgy at the surface of the brain, you could produce red blood cells in the CSF--but so what?


Yes, I am saying that if the ESWL can cause damage to the kidney which produces haematuria then this ballistic pressure should be able to do the same. My assertion is that the former is not surprising and the latter would not be surprising either, if it existed according the parameters of the theory.
I have assisted the urologists with the setting up of these units in theatre: unless it is an all-in-one unit, it is done by iso-centring a radio-opaque spike to the "focus" of the ESWL by means of fluoroscopy. I would do the fluorsocopy set up.
I've been in the theatre when they do this procedure and I have placed my hand in the curvature of the unit while it is operating.
If you stand there and watch the machine and the patient you can get an inkling about the likely cause of the haematuria in these cases (not pre-existing, but as a result of the procedure).
The patient has to breathe, yes? The kidneys (believe it or not) move with respiration. Even with the best gating of ESWL pulses to respiration you are going to get some unwanted damage. It's pesky details like that which seem to crop up in your mind if you have actually worked in a hospital.

One thing that ESWL does teach us about the theory of BSW? ESWL is only possible because shockwaves propagate through the human body with minimal loss of energy; that seems to be a mark against the idea that the shockwave is "dampened" as it passes through tissue.

Do you actually believe what you just posted?

(If I have perhaps misunderstood, and you mean that ESWL of gallstones routinely leads to hematuria, then I apologize for my foolishness. If I have not misunderstood, then perhaps I must pass the fool's cap along...)

You have misunderstood more than that, apology accepted.

Odd Job
September 11, 2011, 06:08 PM
JohnKSa says

That seems a logical extension of the assumptions. And it doesn't hurt the theory, it actually provides a possible explanation of why the effect isn't seen reliably even with solid torso hits. You would have to hit an area with a large blood vessel surrounded by a certain type of tissue in order to have a chance of seeing the effect. Hit an area with the right type of tissue but no large blood vessel--no significant effect. Hit an area with a large blood vessel but not enough of the right type of tissue--no significant effect.

and

There are a lot of very large blood vessels that run through the abdomen, and lots of fluid-filled tissues there as well.

Interesting musings, not part of Courtney's original theory. What tissues do you reckon are needed around these blood vessels (and by extension, where do you think people should be aiming if they want to maximise the potential for a BPW incapacitation)?

Loosedhorse
September 11, 2011, 06:31 PM
Yes, I am saying that if the ESWL can cause damage to the kidney which produces haematuria then this ballistic pressure should be able to do the same. My assertion is that the former is not surprising and the latter would not be surprising either, if it existed according the parameters of the theorySince you used it on me: do you actually believe what you just posted?

The energy of ESWL is focused in one small spot: in EXACTLY the right place to cause hematuria, and only used in a patient who ALREADY has good reason to have hematuria even without ESWL. If you can't see how that's different from BSW, then I'm sure I can't help.

Oh, and I take it you have no evidence of routine hematuria in patients who have had ESWL for gallstones? I did ask...I guess you were just too embarrassed to answer? (I personally thought the incidence was about 5%.)if the ESWL can cause damage to the kidneyAre you saying that it damages the kidney GENERALLY, as opposed to damaging only the tiny volume of the kidney into which the energy is focused? You have presented no reason to supposed that.Do you actually believe what you just posted?Of course: if the shock wave was significantly dampened in the body, then a) the renal stone could not be disrupted, because the energy would not reach it, AND b) the intervening tissue between the skin surface and the calculus woud be damaged as it absorbed the energy.

But neither of these are the case, because shock waves ARE efficiently propagated through the tissues. From Medscape:The efficacy of ESWL lies in its ability to pulverize calculi in vivo into smaller fragments, which the body can then expulse spontaneously. Shockwaves are generated and then focused onto a point within the body. The shockwaves propagate through the body with negligible dissipation of energy...[emphasis added]
Maybe you should call them up and tell them how wrong they are?

Oh, don't worry: the fool's cap looks good on you--like you were born to wear it! :DIt's pesky details like that which seem to crop up in your mind if you have actually worked in a hospital.This is the internet: why should I believe that you have worked in a hospital? Why should you believe I haven't? These appeals--believe what I say because of who I say I am? Pretty tiresome.

JohnKSa
September 11, 2011, 06:43 PM
Interesting musings, not part of Courtney's original theory.You've characterized them properly, in my opinion, as musings.

In a sense it's extended from some of Courtney's experiments where he used water as a coupling medium to transfer BPW from the bullet to the test subject.What tissues do you reckon are needed around these blood vessels (and by extension, where do you think people should be aiming if they want to maximise the potential for a BPW incapacitation)?It makes sense to me that the more the situation is like a blood vessel in a bucket of water with a bullet being shot into the water, the more coupling will take place. I doubt connective tissue, bones, or even muscle couple very well; I'd guess that soft tissue like the liver, pancreas, maybe fatty tissue couple a lot better.

As far as the latter half of the question, I'd say it's premature to look at BPW in that light at this time. I don't believe it's understood well enough to recommend that people to start altering their handgun self-defense tactics in an attempt to achieve it.

The only thing I think is advisable, in light of the possibilities offered by BPW, is to use expanding ammunition in handguns as long as it doesn't unduly limit penetration. Of course that's been pretty well accepted as the prudent course of action long before anyone began discussing/debating BPW.

I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality. But I'm less interested in it (at least at this time) as a practical method for trying to significantly improve the chances of stopping an attacker with a handgun.

Shawn Dodson
September 11, 2011, 07:08 PM
I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality.

When "beaten against reality" there is greater evidence against BPW as a mechanism of incapacitation than evidence to support it.

JohnKSa
September 11, 2011, 07:45 PM
When "beaten against reality" there is greater evidence against BPW as a mechanism of incapacitation than evidence to support it.Coupla things...

I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

Which gets to my second observation. It seems there's often confusion/obfuscation about the specific definition of what constitutes "evidence against" something. It's one thing to say that there is evidence that a particular effect isn't a consistent or dependable mechanism for incapacitation--and that's true of a number of terminal effects that unquestionably do exist. It's another thing entirely to go the extra step and say that same evidence is also evidence that the effect isn't a mechanism for incapacitation at all--yet it does not seem to be uncommon for that distinction to be blurred.

tipoc
September 11, 2011, 08:06 PM
It's unfortunate, in my opinion, that these discussions can tend to jump to the edges of what is known and move straight past what is known and observed when that is interesting enough. Some of Courtney's observations are at those edges and have little evidence to support them. I wish him luck in his studies because one way or the other they can be of value but in terms of developments in ammo I don't think that there is much there.

In the video I link to below the fellas over to Brass Fetcher have used 20% ballistic gelatin in order to enhance the visual effect. 10% is what is normally used for testing because that most closely resembles the density of human tissue. The gelatin blocks sit on 1"x1" blocks and the spaces between them are also 1"x1" or so they have told me.

http://www.youtube.com/watch?v=h23T1XS7tUo

Note what the bullet does.

You can view more here...

http://www.brassfetcher.com/index_files/Page1950.htm

In addition to the damage caused directly by the bullets passage there is also damage caused by the rapid and violent expansion of gelatin (or tissue in a mammal) as the bullet forces material out of it's way and in all directions. This action creates, violently, a temporary stretch cavity that does cause damage to tissue and bone not directly touched by the bullet. This damage and the amount of it is what the debate is about.

There is, or should be, no debate about whether damage is caused by the "wave" or "hydraulic" action, whatever one may call it, caused by the passage of the bullet to tissue not directly touched by the bullet. The damage has been too often observed and documented over generations for folks to realistically deny that tissue is damaged. (A good many hunters stuck with the 30-30 on deer over more modern, smaller and faster rounds, due to the destruction of too much tissue by the latter and the loss of edible meat.)

The problem is that the extent of the damage varies quite a bit. It matters where the bullet strikes. It matters how well hydrated a person or animal is. Temperature matters. It matters whether the animal or person being struck is at rest or violently active at the time they are hit. Caliber, velocity and bullet construction obviously matter. By "matter" I mean that these factors and others effect the extent of the damage.

So can there be remote damage to the nervous system as a result of the "pressure wave" created by the bullets passage as Courtney posits? Yep there could be. Col. Chamberlin, who Courtney cites, thought so. Chamberlin also thought it could not be relied on for incapacitation because of the many variables that I mentioned. What could be relied on was where you put the bullet and the choice of caliber and bullet type.

tipoc

Loosedhorse
September 11, 2011, 08:34 PM
Yep there could be. Col. Chamberlin, who Courtney cites, thought so. Chamberlin also thought it could not be relied on for incapacitation because of the many variables that I mentioned. What could be relied on was where you put the bullet and the choice of caliber and bullet type.Can I have an "Amen!"?

[Just one more word about hematuria: this paper (http://www.ncbi.nlm.nih.gov/pubmed/15371841) (discussed in this review (http://findarticles.com/p/articles/mi_7453/is_200808/ai_n32290458/?tag=mantle_skin;content)) found that over 50% of patients did NOT have hematuria--gross or microscopic--after they had received...penetrating injury to the kidney itself!

So the absence of hematuria = no renal injury theory takes a big hit! (Of course, it could be another Czech student, perhaps?)]

Odd Job
September 12, 2011, 04:17 AM
JohnKSa says

As far as the latter half of the question, I'd say it's premature to look at BPW in that light at this time. I don't believe it's understood well enough to recommend that people to start altering their handgun self-defense tactics in an attempt to achieve it.

The only thing I think is advisable, in light of the possibilities offered by BPW, is to use expanding ammunition in handguns as long as it doesn't unduly limit penetration. Of course that's been pretty well accepted as the prudent course of action long before anyone began discussing/debating BPW.

I'm very interested in BPW because it explains some anomalies and contradictions that turn up when the theories of stopping power put forth by the "permanent wound channel is everything" crowd are beaten against reality. But I'm less interested in it (at least at this time) as a practical method for trying to significantly improve the chances of stopping an attacker with a handgun.

As an extension of Courtney's theory then, it needs a lot of work and experimentation to prove. I don't know if it is possible to do.
I'm at least glad to see that you don't seem to be advocating placement of shots in the abdomen.
If people stick with adequate penetration and good JHPs, that is all that can be asked. But with the (supposed/proposed) limitations that you set out earlier in your extended theory, I think it is a moot discussion.

Odd Job
September 12, 2011, 04:26 AM
This is the internet: why should I believe that you have worked in a hospital? Why should you believe I haven't? These appeals--believe what I say because of who I say I am? Pretty tiresome.

Actually it is about experience, research and relevant observations.
I've been there. I can tell by your posts that you have not.

Oh, don't worry: the fool's cap looks good on you--like you were born to wear it!

You just keep thinking that. I'm not going to bother with you any longer.

Norrick
September 12, 2011, 06:50 AM
I don't know the claimed specifics but I do believe it has some wounding effects. Disruption of valves who is to say. I remember hearing about a man who induced a stroke because he was pushing too hard while going #2. I know that the first time I tried doing a jump on my snowboard I belly flopped onto packed snow and the hit to the abdomen sent a sudden rush of pressure to my head. I had a bad headache for the rest of the day and I hadn't even hit my head.

I think in order to produce that effect a bullet would need to hit center mass (where all the fluids and blood are pooled, so to speak)so I don't think the added shock will have any substantial added effect on the already poor chances of said badguy/animal.

MachIVshooter
September 12, 2011, 10:15 AM
The vagus nerve originates in the brainstem, so anything that suppresses the brainstem will suppress the vagus nerve.

First, Vagus vs. Vegas; Have you ever posted from a "smart phone"? "Vagus" isn't in it's dictionary, and I don't always catch things that have been auto-corrected. Your snark, however, is not appreciated.

Secondly, the Vagus nerve is one of twelve cranial nerves, and it does not originate in the brain stem. Wiki actually has a pretty good (short) article on it:

http://en.wikipedia.org/wiki/Vagus_nerve

Third, the parasympathetic nervous system most certainly can control the release of adrenaline.


Of course: if the shock wave was significantly dampened in the body, then a) the renal stone could not be disrupted, because the energy would not reach it, AND b) the intervening tissue between the skin surface and the calculus woud be damaged as it absorbed the energy.

Do you understand the difference between a hydraulic shock wave and an acoustic shock wave? You cannot compare the sound waves used to crumble kidney stones to the shock waves generated by a ballistic impact. They aren't whacking the kidney in order to generate a stone-busting pressure wave; The accoustic waves that a Lithotriptor produces are intensly focused and have greatest effect on more dense and rigid objects, while a BPW would affect soft tissue much more and have little or no effect on bone, etc.

I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

Seen just as many run a good distance with their heart split in half-so would that clearly be evidence that a functioning circulatory system is not necessary for motor function? Because using the smae logic, that it the conclusion we arrive at.

I've also shot a number of animals in the head and watched them run-this definitely flies in the face of any BPW theory for instant incapacitation, as the only release for the pressure developed there is the bullet hole itself. Best example has been feral cats; Two of them were very much alive and moving quickly and deliberately after taking a .22 LR bullet through the cranium at literally point blank range (less than 10 feet).

It also seems that you're asserting under the assumption that there is no significant nervous system outside the scope of spinal cord and brain. In reality, there are many LARGE nerve bundles throughout the body that, when struck by the bullet or secondary missles, or when acted on by a significant temporary cavity resulting from GSW, certainly can cause the animal to act as though he's been struck by Thor's hammer. I'll again reference the 12 cranial nerves. So unless you dissected the animal and verified that absolutley no vital organ or nerve bundle was affected by the bullet, the permanent cavity or the temporary cavity, your theory is mere speculation at best.

Mike1234567
September 12, 2011, 11:11 AM
Differing tissue types react differently to hydrostatic shock. For instance, brain cells are completely different than long-stranded (stretchy/tough) muscle cells. A severe shock to the brain will cause far more ripping, tearing, and liquification than the same shock to muscle tissue which is more prone to temporarily stretching and deformation. Likewise, liver, kidney and other tissue matter will be less able to survive hydrostatic shock than muscle. So, IMHO, the effectiveness of hydrostaic shock is heaviliy dependent on shot placement. But... this has been covered many times.

brickeyee
September 12, 2011, 01:37 PM
The question was why a torso hit would cause an effect in the brain while a neck hit didn't show a stronger effect. If the neck doesn't have the kind of tissues that couple projectile energy into blood vessels very well then that lack of coupling efficiency could mean that a hit in the neck might result in a weaker effect to the brain even though it's closer to the brain than the torso.

Unless you happen to affect the carotid arteries.

Things like this are so specific to each shooting that general conclusions are almost impossible to derive.

There are thousands of variables in play, and even shooting the same gun at the same animal in the same spot may not produce a repeatable result.

As a real science, terminal ballistics is not going to get there for a very long time.

We simply cannot even account for all the tiny changes and the sometimes major effects they create.

Shawn Dodson
September 12, 2011, 06:39 PM
I think anyone who has ever hunted enough or even watched enough hunting shows has seen animals drop instantly from a shot to the body even though the bullet obviously didn't come anywhere near the components of the central nervous system. That is clearly evidence that the CNS was insulted/damaged via some means even though neither the permanent nor temporary wound channel impinged on the CNS. Does it happen all the time--nope, but it DOES happen.

The bullet does not have "to come close" to CNS structures to physically disrupt the CNS. The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.

JohnKSa
September 12, 2011, 11:07 PM
Unless you happen to affect the carotid arteries.I'm not saying it couldn't happen, I was speaking specifically to the comment about why neck injuries didn't seem to create a higher incidence of BPW effects since the neck, being closer, would clearly generate a stronger BPW to the brain. The comment was made that the fact that they didn't seem to was evidence against BPW. I'm not saying that there's no way to couple the energy into the veins in the neck from a neck hit, I'm only suggesting a possible explanation as to why BPW effects might seem less likely as a result of a bullet strike to the neck.There are thousands of variables in play, and even shooting the same gun at the same animal in the same spot may not produce a repeatable result.Yes.The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.Seems reasonable. So those effects are so powerful that they can physically drive a piece of bone against the spinal cord hard enough to cause instant paralysis.

Maybe those effects are also so powerful that if they are focused against blood vessels they might cause a pressure wave to travel through them. ;)

Odd Job
September 13, 2011, 05:23 AM
Shawn Dodson says

The bullet does not have "to come close" to CNS structures to physically disrupt the CNS. The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector), in which they physically collide violently against the spinal cord to produce a concussive effect that causes instant flaccid paralysis.

Are you talking about rifle or handgun injuries?

Loosedhorse
September 13, 2011, 08:13 AM
Secondly, the Vagus nerve is one of twelve cranial nerves, and it does not originate in the brain stem.My goodness you DO go out of your way to make these mistakes! And are so adamant about them.

The cell bodies for the axons of the vagus nerve (its origin) are contained in the nucleus ambiguus, doral nucleus of the vagus, and the nucleus solitarius--all in the brainstem. The nerve itself begins where those axons emerge for the dorsolateral surface of the medulla (at the level of the inferior olive)...and the medulla is part of the braistem. Whether wiki says so or not.Third, the parasympathetic nervous system most certainly can control the release of adrenalineCan? As in, by magic, on certain days?

No, it does NOT. Looks at your own favorite reference, wiki, for pete's sake: the adrenal glands have SYMPATHETIC innervation. Nothing about parasympathetic, and certainly nothing about vagus--your earlier claim (which you have slithered away from?).

Here's your dunce cap. Go stand in the corner.

Can we just say as a blanket statement that everything you say about human anatomy is wrong? I mean, how many mistakes have you made so far? And you're NOT making these mistakes on purpose, as a gag??? Wow: the arrogance of ignorance.The shape of an animal's body can focus the effects of temporary cavitation on spinal bones (in the manner of a parabolic reflector)And where, please, is the evidence of the parabolic-reflector theory of spinal injury? Hey, I'm not saying you're wrong, but aren't you one of the guys dismissing the BSW as unproven? Yet you feel comfortable invoking the deer body as parabolic mirror theory? One unproven theory as disproving a different unproven theory?

And yet there is no similar parabolic effect for human bodies? :confused:;)Actually it is about experience, research and relevant observations.
I've been there. I can tell by your posts that you have not.Okay, now you're not just claiming you worked in a hospital (janitor? Orderly?), but to have done research--perhaps on this very subject? Some published citations would be nice. Otherwise, you're just blowin' smoke.

Sad, really. You're so puffed up with your own self-important "experience" that you feel comfortable attacking me as inexperienced with no support whatever, except your opinion. You can't recognize another's experience? That's your own fault. Well, we've all met your type.

By the way, Mr. Experience, why no comment on the vagus nerve? Why leave that mess for me to clean up? Or isn't that within your vast experience?

Mike1234567
September 13, 2011, 09:48 AM
I wonder if the success of hydrostatic shock is, more simply, a sudden devastating burst in blood pressure which might cause rupturing of blood vessels within the brain.

MachIVshooter
September 13, 2011, 11:01 AM
My goodness you DO go out of your way to make these mistakes! And are so adamant about them.

The cell bodies for the axons of the vagus nerve (its origin) are contained in the nucleus ambiguus, doral nucleus of the vagus, and the nucleus solitarius--all in the brainstem. The nerve itself begins where those axons emerge for the dorsolateral surface of the medulla (at the level of the inferior olive)...and the medulla is part of the braistem. Whether wiki says so or not.

Been going off of memory from casual reading of A&P books years ago. I just cracked it again to check, and my error comes from remembering that the Vagus emerges at the top of the medulla, between it and the pons. I did not recall the pons and midbrain being considered part of the brainstem (and it seems there is some ambiguity about what, besides the medulla, is technically "brainstem")

My recollection of it's control of adrenal respose was backwards; Forgot the vagus serves to counter the increased heartrate caused by adrenaline.

All that said and errors included, my original point remains; General anesthesia does not shut down the entire autonomic nervous system, as was claimed. Anesthesia itself is a peculiar thing, and thats why there are anesthesiologists who do nothing but monitor vitals and administer the entire time. And respirators are not always necessary....

Here's your dunce cap. Go stand in the corner.

Can we just say as a blanket statement that everything you say about human anatomy is wrong? I mean, how many mistakes have you made so far? And you're NOT making these mistakes on purpose, as a gag??? Wow: the arrogance of ignorance.

Can we just make a blanket statement that you're a jerk? The rest of us are trying to have a civil conversation here, but you've directly insulted some of us. Not very high road.

And you still haven't answered whether you understand the difference between an acoustic shock wave and a ballistic shock wave or pressure wave. You do at least get that there are different kinds of waves, yes?

Mike1234567
September 13, 2011, 02:06 PM
Looky What I Found (http://en.wikipedia.org/wiki/Hydrostatic_shock) :)

MachIVshooter
September 13, 2011, 03:38 PM
Looky What I Found

Once again, no one is arguing the presence of a pressure wave, but what it's effects are. Certainly 500 or 1000 PSI would be harmful; Thing is, as the pressure wave travels in a 3-dimensional parabolic shape, the pressure attenuates at an exponential rate. Even excluding the shock-absorbing capabilities of soft tissue and presuming pure liquid, that dissipation is still geometric. Double the volume of the wave, halve the pressure. Double it again from the volume (not diameter or circumference) of the last increase, halve the pressure again (1/2, 1/4, 1/8, etc.) and so on.

Someone with better math skills can probably articulate this more effectively than I can, but this is concept rather than exact, so we'll use simple linear math for it. Now remember that spherical volume is calculated at a factor of 4/3*pie*radius cubed, (roughly 4.19*radius cubed) so a semisphere (hemishpere) is half of that (4.19*Radius cubed/2).

For the purpose of these illustrations with my rudimentary geometry skills 15 years since I studied, we'll use the calculation of a true hemisphere rather than a half ellipsoid with cylindrical base or other shapes that make volume calculations more difficult.

So, if calculating using a .45 cal RN {(4.19*.225cubed)/2}, we have a pressure wave point of origin (POO) resulting from a displacement of .05CI. Suppose the pressure at POO is 1,000 PSI. Increase the area of our pressure wave by a factor of 2 (a .9" semisphere diameter) and now you have a volume of .19CI. Assuming a linear dissipation, we have to take the 1000 PSI we began with and divide it by ~4 (.19/.05). So only .225" from the POO, our pressure is reduced to 250 PSI. By the time you get an inch away from the POO (1.225" radius semisphere with a volume of 3.85CI), pressure is down to ~13 PSI.

As I said, my math is not as good as some of our members who could accurately calculate with a correct elliptiod (and superscript that I can't figure out how to get). The point remains.

Some variables to consider that require better math skills and a lot more specific details than I (we?) have at hand:

Causing pressure to be greater than the simple equation:

-The math I did is very simple and assumes a static pressure; The velocity and magnuitude of the pressure wave will affect the pressure as it travels outward, resulting in a pressure differential on either side of the wave with greater pressure on the outside.

-The pressure will not be equal across the arc of the wave; it will be greatest at the front.

Causing the loss of pressure to be more dramatic than simple math indicates:

-As with the pressure, the magnitude and velocity of the wave will decrease as it travels; Drop a boulder of, say, 50 pounds from a height of 5 feet into a 50,000 gallon pond, you get a big splash and fast moving wave right next to it, but very small and slow wave at the shoreline.

-Pressure will continue to be generated as the bullet travels deeper, but at a decreasing magnitude as velocity is shed; Countering this, some of that pressure wave will dissipate behind the hemisphere as the bullet penetrates deeper, causing the dissipation to become more spherical, and thus increasing the loss.

-Unlike shooting into a bucket with a homogenous liquid medium, the human body is a conglomeration of different tissues that are separated by membranes and other fascia, as well as just space. They're also all contained within a flexible, expandable unit and able to compress/expand and absorb impact themselves; Every part of the human body is designed to absorb and dissipate impact and pressure to prevent injury (The exception being the brain, which is contained rigidly and does not tolerate much pressure). Now, Imagine the hydraulic shock of shooting a water ballon filled with ballistic gelatin. Then imagine what the effect will be on a gelatin-filled water balloon placed next to the one that is impacted, with a couple sheets of clingwrap between them and a 1/8" layer of shaving cream between those sheets. Now imagine the pressure that is generated in a thin tube made of, say, latex, filled with water when it is wrapped around the balloon that isn't struck. Can you see where I'm going with this?

JohnKSa
September 14, 2011, 12:07 AM
Suppose the pressure at POO is 1,000 PSI.I think that if you run the numbers you will find that this supposed pressure at the point of origin is a little low.

For what it might be worth to anyone interested in the topic, Courtney runs through similar calculations in this paper.

http://arxiv.org/ftp/physics/papers/0701/0701267.pdf

He also discusses situations which would prevent the pressure from falling off as rapidly as one might expect from calculations based on a purely homogenous target medium.

MachIVshooter
September 14, 2011, 04:01 AM
I think that if you run the numbers you will find that this supposed pressure at the point of origin is a little low.

For what it might be worth to anyone interested in the topic, Courtney runs through similar calculations in this paper.

http://arxiv.org/ftp/physics/papers/0701/0701267.pdf

He also discusses situations which would prevent the pressure from falling off as rapidly as one might expect from calculations based on a purely homogenous target medium.

Ignoring for the moment that I made disclaimers that I was illustrating concept rather than hard data (hence the nice round numbers and simple, linear math), did you actually look at the chart? (Which, BTW, is flawed at a fundamental level; It is titled "peak pressure wave magnitude", but illustrates only peak pressure, not magnitude [size]. Magnitude and pressure are not synonymous). The chart shows the majority of their test results between 400 and 800 PSI peak pressure, and tapering off dramatically over 1,000 PSI.

From his article, and perhaps what you saw that made you believe my round 1,000 figure was low:

Losing 100 ft-lbs of kinetic energy in 0.02 feet of
penetration would create a force of 5,000 lbs because
100 ft-lbs/0.02 ft = 5,000 lbs.

This is so flawed it's not funny:

-100 lbs/.02 ft=5,000 pounds per square foot, which is 35 PSI (5,000/144)

-There is not a simple calculation to turn ft/lbs of kinetic energy into pound of force or pressure; KE variable is found with velocity and mass, force variable is found with distance/ time/acceleration and mass, pressure is force and area:

1 pound dropped from 1 foot generates 1 ft/lb of energy

1 pound force is required to move 1 pound a distance of 1 foot

1 pound per square foot is the pressure generated by a one pound weight distributed over a square foot at earth gravity

-Even if we had the correct force figures for that bullet (nowhere near 5,000), one cannot calculate the pounds per square foot without a variable Courtney ignored; area of application. He does not tell of the contact area of that bullet that is shedding 100 ft/lbs in .2 ft.

-To calculate the pressure of a ballistic projectile in a liquid medium, one needs to incorporate displacement and velocity. Energy doesn't matter; 500 pound weight at 10 FPS generates 777 ft/lbs, a 200 grain bullet at 1320 FPS generates 773 ft/lbs. Do you think that the 10 FPS weight can generate the kind of hydraulic pressure wave the 1,320 FPS bullet can? A static object only dispaces it's own volume, while a fast-moving object will displace a volume far greater than it's own as the medium cannot resume it's static orientation as quickly as it is being displaced. The faster the object, the greater the displacement volume to object volume ratio.

-There is no calculation for the hydraulic pressure a ballistic projectile will generate in a human body; It is wholly dependent on the medium.

Odd Job
September 14, 2011, 05:11 AM
JohnSKa, it seems to me that given the various problems with how Courtney has tried to sell this theory and the way he has shied away from doing experiments that can outright prove it one way or another, there is room for a more sincere investigation into this.
Are you keen to do it (and include your extensions to his theory)?

brickeyee
September 14, 2011, 01:43 PM
This is so flawed it's not funny:

1 pound dropped from 1 foot generates 1 ft/lb of energy

ft-lb, NOT ft/lb

MachIVshooter
September 14, 2011, 02:24 PM
ft-lb, NOT ft/lb

You're gonna spend a lot of time running around this forum and others correcting every post that has denoted it with a slash instead of a dash. Have fun with that.

As long as you're being persnickety, you might look for all of these as well:

ft.lb
lb.ft
ft/lbf
ft-lbf
lb/ft
lb-ft
foot/pound
pound/foot
pound-foot

When you're done with that, there are always the other divisions of imperial and the whole of SI with similar variations in denotation

In denoting units of measurement, the slash DOES NOT indicate division. PSI is often denoted with lbs/in2 (sorry, can't get the superscript). Inches or millimeters of mercury is denoted in/hg or mm/hg. The list goes on. And on.

SN13
September 14, 2011, 02:31 PM
I don't even need to read this entire thread... This thread should be shut down for so much misinformation about physics....

If you really think that a bullet has more energy imparted onto it than onto the gun firing it, please watch this Video of a man standing on ONE foot taking a .308 to the Torso (http://www.youtube.com/watch?v=Yd9-hreCYz8).

Mike1234567
September 14, 2011, 02:45 PM
pound-feet :D

MachIVshooter
September 14, 2011, 02:52 PM
If you really think that a bullet has more energy imparted onto it than onto the gun firing it,

Again, the energy vs. force thing.

The force driving the bullet forward is equal to the force driving the gun backward. However, due to the mass, the rate of acceleration is inversely proportionate; The much lighter bullet is accelerated much faster and to a much higher velocity. Because energy is velocity squared times mass, the bullet produces much more energy.

Force is mass and acceleration; 1 pound force (~32 poundals) is what is required to accelerate a 1 pound mass at a rate ~32 feet per second squared (or 32 pounds at 1 FPS squared). The pound-force is based on the rate of acceleration for standard gravity at 32.174049 feet per second per second, which is why one can state that a pound dropped from a height of 1 foot will exert one foot pound, because gravity is acting on that mass with 1 pound-force.

However, a pound will not have accelerated to 32 FPS when dropped from a height of one foot, because it began at 0 FPS and is accelerating at the rate of 32 FPS per second, not 32 FPS per foot. It will have attained a velocity of ~8 FPS after 1 foot of travel and covered that distance in a quarter of a second.

Force exists in the absence of motion; Kinetic energy cannot; Force can be exerted on an object but,be insufficient to move it. The force is still there, still acting.

Kinetic energy can be calculated if mass, force and distance are known, because the force vector is a constant; Over a specific distance at a given rate of acceleration, the velocity can be determined, and so can the kinetic energy.

Then there's momentum, which is mass times velocity.

Momentum and kinetic energy can be used to calculate the force a bullet exerts on a target, but this is not the same as the energy it impacts with; A bullet that impacts with 500 ft/lbs does not exert 500 pounds of force, That bullet cannot accelerate a 500 pound object it hits at the rate of 32 feet per second per second. In fact, it can barely budge something that large.

My math isn't good enough to calculate the force a 230 gr. bullet at 1,000 FPS (510 ft/lbs) can exert without spending more time on it that I have to spare at present, but I'm sure someone can. I'm not sure how one figures the force of an object that rapidly decelerates from a high velocity on impact. I know it's momentum (pound-feet-second) over time, more or less.

This should clear up some of the unit confusion:

http://www.racquetresearch.com/units.htm

Loosedhorse
September 14, 2011, 06:59 PM
Been going off of memory from casual reading of A&P books years agoWell, this is progress. Finally an admission that you have been presenting errors as fact.it seems there is some ambiguity about what, besides the medulla, is technically "brainstem"There is no ambiguity: the midbrain, pons, and medulla (oblongata) comprise the brainstem.General anesthesia does not shut down the entire autonomic nervous system, as was claimed.Claimed by whom? Where? My quote was this:General anesthesia suppresses brainstem function, which is why an artificial respirator must be employed. So, general anesthesia would prevent a brainstem-mediated general (endocrine) release of adrenaline into the blood, or other brainstem-mediated changes in blood pressure.So, just like you have been making errors in anatomy, you are now apparently claiming I said things that I did not. You're really helping your credibility. :rolleyes:Can we just make a blanket statement that you're a jerk?Who's this "we"? YOU can make whatever blanket statement you want.

Let's see: we have one poster, you, who repeatedly and unapologetically makes obviously false statements about human anatomy; and when that fails, makes false statements about what another poster "claimed"; and then, when that fails, resorts to ad hominem name-calling (usually taken to be an admission that the person has no logical, cogent response to the points made).

And we have another poster, me, tirelessly correcting those errors. And you award the title of jerk to me? Okay.And you still haven't answered whether you understand the difference between an acoustic shock wave and a ballistic shock wave or pressure wave. I was trying to spare you yet more embarrassment (if you in fact can ever be embarrassed). Tell you what: you explain to us the difference between these waves, okay? (For a bonus, you can explain why any such differences are important to our discussion.) After all, you've been doing so well with anatomy...! However, due to the mass, the rate of acceleration is inversely proportionate; The much lighter bullet is accelerated much faster and to a much higher velocity. Because energy is velocity squared times mass, the bullet produces much more energy.Well, guess what? We agree. Well said.

brickeyee
September 14, 2011, 11:06 PM
It is hard to take anyone seriously who cannot even get the units correct.

It really matters.

JohnKSa
September 15, 2011, 12:22 AM
Are you keen to do it (and include your extensions to his theory)?He's done some practical experimentation that provided interesting results. Enough to demonstrate that his basic premise has value. Not necessarily enough to demonstrate that it could be turned into something practical.

I have neither the resources nor the inclination to attempt to verify his results given that I'm not at all certain there's much of a way to turn the results into something practical in terms of handgun stopping power. I saw his experimentation and theory primarily as expanding the understanding of terminal ballistics by providing explanations for effects that are fairly commonly observed but not well-explained by other theories of stopping power.Losing 100 ft-lbs of kinetic energy in 0.02 feet of
penetration would create a force of 5,000 lbs because
100 ft-lbs/0.02 ft = 5,000 lbs.

This is so flawed it's not funny:

-100 lbs/.02 ft=5,000 pounds per square foot, which is 35 PSI (5,000/144)He's not talking about psi/pressure, he's talking about the fact that kinetic energy divided by the distance required to stop the projectile is proportional to the force applied to the target medium by the projectile.There is not a simple calculation to turn ft/lbs of kinetic energy into pound of forceCertainly there is, and it's VERY basic physics.KE variable is found with velocity and mass, force variable is found with distance/ time/acceleration and mass, If you work out the units, you'll find that Kinetic Energy and Force are very closely related.

Force = mass x acceleration

Acceleration = speed/time
Speed = distance/time

Kinetic energy = mass x speed x speed

Kinetic energy = mass x speed x distance/time

Rearranging terms

Kinetic energy = mass x speed/time x distance

Since speed/time = acceleration...

Kinetic Energy = mass x acceleration x distance

And now it's plain that

Force = Kinetic energy / distance.

Exactly what Courtney's calculations show. Not surprising since he has a doctorate in physics.

By the way, Force can also be related to momentum. Force is proportional to the momentum of the projectile divided by the time it takes to stop the projectile.

Force = Momentum / timeI'm not sure how one figures the force of an object that rapidly decelerates from a high velocity on impact.That's apparent. What's confusing is that, knowing that you didn't understand the science, you would think it made sense to try to nitpick basic math and physics calculations in a published and peer-reviewed document written by two persons with doctorates in physics from MIT and Harvard.

Vern Humphrey
September 15, 2011, 10:00 AM
I wonder if the success of hydrostatic shock is, more simply, a sudden devastating burst in blood pressure which might cause rupturing of blood vessels within the brain.
You can settle that by a simple expiment -- when you shoot a deer this fall and saw off the top of the skull with the attached antlers, look to see if there is evidence of ruptured blood vessels in the brain.

Mike1234567
September 15, 2011, 10:26 AM
My head hurts...

MachIVshooter
September 15, 2011, 12:59 PM
He's not talking about psi/pressure, he's talking about the fact that kinetic energy divided by the distance required to stop the projectile is proportional to the force applied to the target medium by the projectile.

First, I was addressing the assertions that my 1,000 PSI POO figure was low, which seems to have come from seeing that 5,000 pound force figure, because the chart reflects 1,000 to be on the high end. That was only to illustrate a point; I know the difference between pound force and pound per square foot, as I've demonstrated.

Second, are we are to believe that if you fire a bullet developing 100 ft/lbs into the back of a 5000 pound vehicle and the bullet stops within .2 ft, that vehicle will accelerate at a rate of 32 FPS per second? Because that's what 5000 pounds force will do.

Reality shows that a bullet certainly cannot move an object that size, no matter how deep or shallow the penetration, even with much more than 100 ft/lbs KE.

Force = Kinetic energy / distance.

So a bullet that is stopped at 0.000 Feet penetration exerts no force, and one that travels 1 foot and expends it's 100 ft/lbs generates 100 pounds of force, but that bullet that only travels 0.02 ft exerts 5000 pounds force? Seems a bit flawed, doesn't it?

By the way, Force can also be related to momentum. Force is proportional to the momentum of the projectile divided by the time it takes to stop the projectile.

Force = Momentum / time

Except Courtney didn't incorporate time or momentum, only distance and KE with an unknown velocity and mass, which leaves the time and momentum a mystery.

Momentum cannot be found without either A) bullet weight and velocity, B) Bulet weight and KE or C) velocity and KE. Since all he gives is KE, you cannot find momentum and therefore cannot solve for force. Two projectiles that develop the same KE can have very different momentum:

a 20 gr. bullet at 4,100 FPS generates a KE of 747 with a momentum of 11.71 pounds/FPS.

a 200 gr. bullet at 1,300 FPS generates a KE of 750 with a momentum of 37.14 pounds/FPS

Force = Momentum / time

Let's use the momentum of a 230 gr. pill at 1,000 FPS. That gives us a momentum of 33 pounds/FPS. Now we divide 33 by, say, 5 milliseconds (0.005 Seconds) that it would take to stop the bullet. Does 211,200 poundals sound right to you? That a .45 ACP slug can accelerate a 3+ ton object to 22 MPH in one second?

Since you seem to believe that you're so good at math (the numbers are a bit more complicated than these over-simplified equations), why don't you solve for force with the aforementioned 230 gr. slug at 1,000 FPS.

Who's this "we"? YOU can make whatever blanket statement you want.

The same we you were referring to when you insulted me.

Odd Job
September 15, 2011, 03:29 PM
Vern wisely observes:

You can settle that by a simple expiment -- when you shoot a deer this fall and saw off the top of the skull with the attached antlers, look to see if there is evidence of ruptured blood vessels in the brain.

Indeed that's what I suggested to Michael Courtney. Shoot one deer with a bullet, one with an arrow, have the heads analysed by a veterinarian.
If that's positive, I'll say right here that the ballistic pressure wave exists and that gunshots to the chest can cause brain haemorrhages (even micro) and the debate will be over.
You have to ask why it hasn't been done...

Loosedhorse
September 15, 2011, 03:55 PM
I wonder if the success of hydrostatic shock is, more simply, a sudden devastating burst in blood pressure which might cause rupturing of blood vessels within the brain. Mike, I think that theory was long ago discarded. (Knowing that, and knowing what the results would show no rupture, some here have still suggested you try it.)

It might be instructive to shoot animals and look for microscopic differences in the vessels of those animals that collapsed immediately (or within, say, 5 seconds) compared to those animals who fell later. You might need a lot of animals to distinguish consistent patterns from random differences, and now you're gettng expensive...

And the PETA folks will be on you!

And then we'd still have the bugaboo that some humans who suffer concussion have no abnormal imaging findings--so why should we be assured there will be microscopic pathological findings?

Vern Humphrey
September 15, 2011, 04:00 PM
You have to ask why it hasn't been done...
If we did that (examine the brain of a gun shot deer for evidence of hydrostatic shock) we'd end all debate and gun forums would wither and die.;)

Mike1234567
September 15, 2011, 04:36 PM
Anyone have access to a MRI machine?:D

Vern Humphrey
September 15, 2011, 04:55 PM
Anyone have access to a MRI machine?
No need, since we're not talking about examining a live deer -- we're talking about doing a necropsy. All you need for that is a microscope and some staining fluid.

MachIVshooter
September 15, 2011, 04:58 PM
Here, let's take a crack at this using Courtney's 100 ft/lbs imparted in .02 ft. number:

A 45 gr. projectile at 1,000 FPS develops almost exactly 100 ft/lbs (99.9)

We'll use a 5,000 pound mass suspended (no rolling resistance)

At 1,000 FPS, that bullet will travel 1 ft in 1 millisecond, so it will travel .02 ft. in 20 microseconds, and we'll assume that's where it stops for "complete energy transfer". Obviously, the bullet will take slightly longer to make that depth, since it is decelerating during that 1/4" of penetration, but that's a whole nother equation. And, of course, Courtney has proposed projectile that sheds 100 ft/lbs in that .02 ft, but does not tell us what the total KE was, nor did he give us the projectile weight or velocity, so we can't know the time it took to reach that depth.

The math tells us the 5,000 pound mass is ~777,778 times that of the bullet

This means the bullet's velocity, once imbedded in the mass, must be divided by the factor of it's mass against the one it's embedding into plus the bullet's mass (employing conservation of momentum):

5000x7000=35,000,000 grains, plus the bullet

35,000,045/45=777,779 ratio

1,000 FPS/777,779=0.001257 FPS

So, in theory, this bullet will accelerate that mass to that velocity in 0.00002 seconds. Agreed?

Divide the velocity by the time it takes to reach that velocity and we get the rate of acceleration per second:

0.001257/0.00002=64.3 fps per second

Now we divide 64.3 FPS by 32.174 FPS that is the base velocity for pound force

64.3/32.174=1.9985

To find pound force required for that acceleration, we multiply mass by that coefficient

1.9985*5,000=9,992

So, by the math and confimed by This calculator (http://www.ajdesigner.com/phpforce/force_equation.php), to accelerate that 5,000 pound mass at that rate requires almost 10,000 pound force.

Now, the problem with trying to calculate the force using simple math of energy and distance over time is that it only tells us the maximum velocity the 5,000 pound object will reach. Simple math suggests that it will accelerate to that velocity in the same amount of time that it takes for the bullet to decelerate from 1,000 FPS to 0 FPS, but that directly conflicts with the 100 ft/lbs in .02 ft.= 5,000 pound force.

Let's try this again, but with a 100 pound mass instead of 5,000

100x7000+45=700,045 grains
700,045/45=15,557 ratio
1000/15,557=0.06428 FPS velocity of the 100 lb mass
0.06428/.00002=3,214 FPS per second rate of acceleration

9,989 pound force is required to accelerate a 100 pound mass at 3,214 FPS per second.

Of course, anyone who's been shooting knows full well that a smaller object can be accelerated by the bullet, while a larger one cannot.

Let's do it one more time with the 100 pound mass, but a 90 gr. bullet at 707 FPS (100 ft/lbs)

100x7000+90=700,090 grains
700,090/90=7,779 ratio
707/7779=0.09089 FPS velocity of the 100 lb mass
0.09089/.00002829=3,213 FPS per second rate of acceleration
3,213/32.174=99.86
99.86*100=9,986 pound force

So, with a slower but heavier bullet making the same KE, but having greater momentum, we get roughly the same force? The 45 gr. bullet has a momentum of 6.43, while the 90 gr. has 9.09 pounds-ft/sec momentum.

Now let's really go nuts with the momentum thing using an automobile:

a 3,000 pound vehicle traveling at 1.4646 MPH generates 100 ft/lbs of energy

since momentum=mass*velocity, it has a momentum of 4,394 pounds-ft/sec

So, since it has the same energy, are we to believe that that slow-moving automobile has exactly the same capability of accelerating another mass as the 45 gr./1,000 FPS bullet and the 90 gr./707 FPS bullet?

Or are we to go with the theory that force=KE/distance, and since the car will not penetrate that object at all and imparts it's energy in 0.000...... seconds, that it has no force? Because that's how Courtney's math works out; No penetration=no force and deeper penetration=less force. Kinda goes against conservation of energy, doesn't it?

Now, since I have a little time, we'll run the numbers again accounting for deceleration, but, since Courtney didn't specify that the bullet stopped in .02 feet, and since according to John that's irrelevant, because it's all about the KE dump and distance, we'll use on that doesn't stop. Let's go with a 9mm 115 gr. at 1,200 FPS, producing 368 ft/lbs. If that bullet dumps 100 ft/lbs in the first .02 feet (1/4"), that means it's velocity has been reduced to 1,043 FPS, so it lost 157 FPS in 1/4". That gives us an average velocity of 1171.5 FPS over the 17 microseconds it took to travel that distance and impart that energy.

We'll use our 100 pound mass again, but because the bullet didn't stop, we'll exclude it's weight from the calculation.

So:

100x7000=700,000 grains object
700,000/115=6,087ratio

Now, because the bullet didn't stop, but imparted 157 FPS of it's velocity into the object, we have to change our math a little:

157/6,087=0.02579 FPS velocity of the 100 lb mass
0.02579/.000017=1,517 FPS per second rate of acceleration

1517/32.174=47.14

47.174*100=4,714 pound force

Hmmm.....still not 5,000, even with calculations accounting for deceleration.

How about a .45 ACP 230 gr. @ 830 FPSfor 352 ft/lbs?

still a 700,000 grain object, so now we have a 3.043 bullet to object weight ratio
For the bullet to penetrate .02 feet and shed 100 ft/lbs, it's velocity is reduced to 671 FPS and it takes .00002665 seconds to traverse that 1/4". That's a velocity differential of 159 FPS imparted on the object, so:

159/3043=0.05225 FPS in .00002665 seconds

0.05225/0.00002665=1,961

1,961/32.174=60.95 FPS per second

60.95*100=6,095 pound force

So how, with both the 9mm load and the .45 load "dumping" 100 ft/lbs in .02 ft, is there such a pound force difference? Because again, according to Courtney and JohnKSA, it should be the same.


Who wants to explain for all of us why John's "Simple equations" don't work here? Because, as I've admitted, I lack the mathematical skills to do so.

Mike1234567
September 15, 2011, 05:00 PM
No need <for MRI>, since we're not talking about examining a live deer -- we're talking about doing a necropsy. All you need for that is a microscope and some staining fluid.

MRIs are often used in autopsies. It "may" tell enough and it's not as messy.:)

JohnKSa
September 16, 2011, 12:16 AM
First, I was addressing the assertions that my 1,000 PSI POO figure was low, which seems to have come from seeing that 5,000 pound force figure, because the chart reflects 1,000 to be on the high end.Your figure was at the point of origin (POO), the chart does not reflect point of origin energies. Your figure was low the way it was stated.Second, are we are to believe that if you fire a bullet developing 100 ft/lbs into the back of a 5000 pound vehicle and the bullet stops within .2 ft, that vehicle will accelerate at a rate of 32 FPS per second? Because that's what 5000 pounds force will do.I used the calculator you found and it indicates that 5000 poundals of force will accelerate a 5000 lb vehicle at 1fps per second, not 32fps per second. Not too surprising given that F=ma, or F/m=a. 5000/5000 = 1.

AND, that assumes that all of the energy is used creating force that moves the object. In reality much of the force is used up deforming the objects involved and or creating heat and noise as opposed to being used entirely to create motion. In case it's not obvious, this discussion is PRECISELY about collisions that result in deformation because we're interested in the damage done by the bullet.

The simple fact that penetration is a factor here means that treating the collisions as no deformation takes place is not valid in the least.

Which means, in reality, that the actual acceleration will be less even than the 1fps the calculator indicated. Most, if not all, of the energy was used to deform the target, not to move it.So a bullet that is stopped at 0.000 Feet penetration exerts no force,No, theoretically it would exert infinite force. If you divide a non-zero quantity by zero you get infinity.Seems a bit flawed, doesn't it?It seems a bit flawed because you don't understand the physics or apparently even the math involved.Except Courtney didn't incorporate time or momentumI didn't so much as hint that he did. I was trying to point out how badly flawed your assessment of converting kinetic energy to force was and thought it might be worthwhile to throw in the bit about momentum to show how momentum and energy relate.Since all he gives is KE, you cannot find momentum and therefore cannot solve for force. Two projectiles that develop the same KE can have very different momentum:You can calculate force from KE if you know how much distance it took the bullet to stop. I showed you how. Two persons with doctorates in physics from MIT & Harvard showed you how in their paper.

Here's another source.
http://hyperphysics.phy-astr.gsu.edu/hbase/work.html

"Average impact force x distance traveled = change in kinetic energy"

Rearranging the equation by dividing distance traveled on both sides we get:

Average impact force = change in kinetic energy/distance traveled.Or are we to go with the theory that force=KE/distanceYou are laboring under a severe misapprehension. The equation that force = KE/distance is NOT theory in any sense that suggests it might be invalid or might not reflect real-world behavior. It is well-accepted science and has been for a few centuries. It has been carefully verified by experimental methods.

Your lack of understanding of the concepts, science and mathematics does nothing to affect their validity.Because that's how Courtney's math works out; No penetration=no force and deeper penetration=less force. Kinda goes against conservation of energy, doesn't it?You're not going to be able to blame this on Courtney. No penetration equals infinite force.

And it's not "Courtney's math", it's simply math & physics. There's nothing special about his calculations and his understanding and application of physics is just fine.

Look. How about a little bit of reality. You may not like Courtney's conclusions, but there is absolutely nothing wrong with his math, nor his understanding of physics. The paper you're referring to was written by two people with doctorates in physics and has been read and reviewed by other people who understand the math & physics. There's nothing wrong with that aspect of his paper.

It's certainly possible to question his overall conclusions, but the nuts and bolts of his calculations are just fine. If you can't make the math work out, then I can assure you that the problem is on your end.

You're performing calculations that prove nothing other than that you don't understand the basic concepts involved in the physics of moving objects. It's a waste of your time to perform the calculations, a waste of your time to post them and a waste of other people's time to read them.

MachIVshooter
September 16, 2011, 01:10 AM
I used the calculator you found and it indicates that 5000 poundals of force will accelerate a 5000 lb vehicle at 1fps per second, not 32fps per second. Not too surprising given that F=ma, or F/m=a. 5000/5000 = 1.

32.174049 poundals in a pound-force; 5,000 pound force acting on a 5,000 pound mass will accelerate it at 32.174049 FPS per second.

Courtney stated pounds of force.

AND, that assumes an inelastic collision (a purely theoretical concept), not a real-world elastic collision where much of the force can be used up deforming the objects involved as opposed to being used entirely to create motion. In case it's not obvious, this discussion is PRECISELY about elastic collisions because we're interested in the damage done by the bullet.

I understand that, but to say that I'm flawed in using that also implies that Courtney's theory is flawed, because pound-force is a vector, and he submits that his bullet dumping energy turns it into force, and he does not quantify the elastic properties of that impact. We all know that conservation of energy tells us that the energy lost from the bullet is converted in several ways, including pound-force acting on the target, pressure within the target, deformation of the slug, etc.

This is also why I was saying that you can't oversimplify this the way it has been.

I oversimplified to a point using inelastic collisions to demonstrate that calculating pound-force with only energy, distance and time that way will give different results if you change other variables like velocity and bullet weight.

You're performing calculations that prove nothing other than that you don't understand the basic concepts involved in the physics of moving objects. It's a waste of your time to perform the calculations, a waste of your time to post them and a waste of other people's time to read them.

So show us how it's done.

I honestly did it expecting to get the same numbers, and re-did them a few times to make sure that in rounding a bit I was using enough digits to the right of the decimal that it was not the cause of the different results.

If you can rework the 9mm/115/1,200 and .45 ACP/230/830 both dumping 100 ft/lbs in .02 feet examples somehow to get the 5,000 pounds of force out of both whilst still having the rest add up, then I'll post in the largest, reddest font possible that I was erred.

The paper you're referring to was written by two people with doctorates in physics and has been read and reviewed by other people who understand the math & physics.

Which brings about a point I noticed earlier, but did not mention: In the world of science and medicine, Imperial units are not common in the least. Why wasn't his paper in SI units?

brickeyee
September 16, 2011, 02:27 AM
So show us how it's done.

Pretty hard when you do not understand energy is lb-ft.

Odd Job
September 16, 2011, 07:02 AM
JohnKSa says

I have neither the resources nor the inclination to attempt to verify his results given that I'm not at all certain there's much of a way to turn the results into something practical in terms of handgun stopping power. I saw his experimentation and theory primarily as expanding the understanding of terminal ballistics by providing explanations for effects that are fairly commonly observed but not well-explained by other theories of stopping power.

I understand.

Vern says

If we did that (examine the brain of a gun shot deer for evidence of hydrostatic shock) we'd end all debate and gun forums would wither and die.

We still got 9mm vs .45 and also birdshot for home defense :p

Pasteur
September 16, 2011, 09:49 AM
The experiment has been performed shooting deer in the chest and inspecting the head for vascular damage.

In the present study, vascular damage was observed in the brain that was visible to the unaided eye and that resulted from a remote ballistic impact to the thorax in human-sized animals.

Here, qualitative results are reported for a small field study that isolated a thoracic mechanism for TBI caused by a high strain rate insult in white-tailed deer (Odocoileus virginianus, mass 49-80 kg) in a natural environment. In each of three cases, petechiae were present on the surface of the frontal, occipital and/or left parietal lobes, along with capillary damage in the choroid plexus. The location of the projectile impact to the thorax seemed to affect the degree of damage. This may be due to the proximity to the great vessels. The data reported here provides direct evidence of a thoracic mechanism resulting in gross injury to the cerebral vasculature.

See:
Cerebrovascular injury caused by a high strain rate insult in the thorax. Amy Courtney, Michael Courtney. Cornell University Library. Medical Physics. 2011. arXiv:1105.4738v1

Another interesting 2011 paper reviewing the evidence:

History and evidence regarding hydrostatic shock. Michael Courtney, Amy Courtney. Neurosurgery. February 2011 - Volume 68 - Issue 2 - pp E596-E597.

A myth is an assertion which has either been disproven by careful experiment or for which there is no historical or scientific evidence in cases where it is reasonably expected. Belief in remote effects of penetrating projectiles may have originated with hunters and soldiers, but their reality is now well established in a broad body of scientific literature...

Vern Humphrey
September 16, 2011, 09:51 AM
MRIs are often used in autopsies. It "may" tell enough and it's not as messy
I checked. Mountain View Custom Butchery doesn't have an MRI.;)

Mike1234567
September 16, 2011, 10:28 AM
I checked. Mountain View Custom Butchery doesn't have an MRI.;)
LOL!! I'm sure they don't. But "research" facilities do when it fits their needs.:)

Odd Job
September 16, 2011, 12:32 PM
Pasteur says

Here, qualitative results are reported for a small field study that isolated a thoracic mechanism for TBI caused by a high strain rate insult in white-tailed deer (Odocoileus virginianus, mass 49-80 kg) in a natural environment. In each of three cases, petechiae were present on the surface of the frontal, occipital and/or left parietal lobes, along with capillary damage in the choroid plexus. The location of the projectile impact to the thorax seemed to affect the degree of damage. This may be due to the proximity to the great vessels. The data reported here provides direct evidence of a thoracic mechanism resulting in gross injury to the cerebral vasculature.

Thanks for providing that, Michael Courtney (I know you are traveling incognito, but you and I both know that it is well known who "Pasteur" is)

If what you have reported is true and if the experiments were conducted with integrity and the appropriate veterinary input also, let me be the first to publically state:

Michael Courtney has proved that there is a direct link between gunshot injuries to the thoraces of deer, and findings of cerebro-vascular damage in those deer. That means there must be a ballistic pressure wave.

I am simultaneously astounded that you have waited so long to do it, yet stepped forward and done it nevertheless.

EDIT: it would have been nice to have a control deer taken by arrow, from the same population, and nice also to have these tests done with handgun projectiles matching your original PSI requirement, but nonetheless this is significant and a step in the right direction.
Who did the necropsy?

Loosedhorse
September 16, 2011, 03:05 PM
That means there must be a ballistic pressure wave.

I am simultaneously astounded that you have waited so long to do it, yet stepped forward and done it nevertheless.Why are you not "astounded" at yourself for not having "stepped forward" and referenced this study? If we're going to criticize someone for showing up "late" with pertinent info, then we should criticize everyone else for not knowing about it. It wasn't hidden.

I'd prefer just to thank Pasteur: thanks! The study is here (http://arxiv.org/pdf/1105.4738).

We already knew that there was a ballistic pressure wave, before the mentioning of this study. We already knew that sometimes deer collapse at the moment they're hit. What this study shows is the consistent (over just three animals) finding of grossly visible small vessel injury in the CNS in deer taking thoracic hits with a .257 rifle bullet.

What we don't know is still a lot. Why was the pattern of vascular damage different in each animal? How did each animals behave after being shot--did one collapse immediately, or run and plow its head right into a tree? Is the CNS vascular injury attributable ONLY to the bullet? What relationship does such injury have to supposed BSW-medated collapse? What would happen with a handgun round? Should we assume that similar cerebrovascular injury happen in humans?

Just trying to keep track of (and differentiate among) what we know we know, what we think we know, and what we know we don't know.

Vern Humphrey
September 16, 2011, 05:07 PM
LOL!! I'm sure they don't. But "research" facilities do when it fits their needs.
The closest research facility is at Toad Suck Ferry.:p

MachIVshooter
September 16, 2011, 06:26 PM
We already knew that there was a ballistic pressure wave, before the mentioning of this study. We already knew that sometimes deer collapse at the moment they're hit. What this study shows is the consistent (over just three animals) finding of grossly visible small vessel injury in the CNS in deer taking thoracic hits with a .257 rifle bullet.

What we don't know is still a lot. Why was the pattern of vascular damage different in each animal? How did each animals behave after being shot--did one collapse immediately, or run and plow its heads right into a tree? Is the CNS vascular injury attributable ONLY to the bullet? What relationship does such injury have to supposed BSW-medated collapse? What would happen with a handgun round? Should we assume that similar cerebrovascular injury happen in humans?

Well, I definitely agree with you here.

One question: Was the study only three animals, or were there more and "in each of three cases" refers to three out of however many where the hemorrhaging was present? I went to the site provided, and that information is not available. Can we access the rest of the study?

Your best point is that we don't know how the animals reacted, and so don't know if the BPW (not argued) causing hemorrhaging (contested) causes immediate or extrememly rapid incapacitation (widely doubted).

Additionally, since it was "in their natural environemt" and therefore lacking controls, how do we know that, as you said, the deer didn't plow into something and cause the injury that way? And if not, how do we know that it was BPW and not extreme blood pressure that was the result of an adrenaline response to the trauma that caused the vessels to rupture? Since adrenaline not only increases heartrate and BP, but is also a vasoconstrictor, how do we rule out it's effects on these animals?

Perhaps a stretch here, but could it even have been that these three deer were bucks during the rut, and the injuries were caused by smashing their heads together prior to being shot?

I've said before and I'll say again that I don't personally and haven't seen anyone else question the presence of the BPW, but what it's effects are. I really don't think the testing in a natural environment can prove that it was the BPW that caused the petechiae. Can't rule out other possibilities without a more controlled experiment.

Odd Job
September 16, 2011, 07:32 PM
LoosedHorse asks

Why are you not "astounded" at yourself for not having "stepped forward" and referenced this study? If we're going to criticize someone for showing up "late" with pertinent info, then we should criticize everyone else for not knowing about it. It wasn't hidden.


Well I didn't see it, it's as simple as that. Evidently, neither did you or you would have posted it yourself way before we got to page 8 of this thread.

MachIVShooter asks

Additionally, since it was "in their natural environemt" and therefore lacking controls, how do we know that, as you said, the deer didn't plow into something and cause the injury that way?

Controls would have been nice, yes. And some timing for when they dropped. The cherry on top would have been a number of handgun-shot deer with cerebral flags, and one or two controls shot with arrows and no flags.
Nonetheless he is on the right track now, can't be too churlish about it. It's a small sample, but that is tangible evidence if the proviso in my previous post is met.

JohnKSa
September 16, 2011, 11:35 PM
So show us how it's done.The paper shows how to do the calculations you are interested in and you can find information about force, energy, momentum and their relationships all over the web.Courtney's theory is flawed...No and no. No, it's not "Courtney's theory". No, it's not flawed.

The real problem is that you have some sort of mental block about kinetic energy. I honestly think that you believe someone invented it, and the equations that deal with it, just to screw with people who are trying to understand terminal ballistics--in order to make things confusing and misleading. It's simply not true, and until you get past that issue you're not going to make any progress in the direction of understanding the basics of projectile physics.

MachIVshooter
September 17, 2011, 12:04 AM
The real problem is that you have some sort of mental block about kinetic energy. I honestly think that you believe someone invented it, and the equations that deal with it, just to screw with people who are trying to understand terminal ballistics--in order to make things confusing and misleading. It's simply not true, and until you get past that issue you're not going to make any progress in the direction of understanding the basics of projectile physics.

Kinetic energy was one of the fisrt things I understood about ballistics, and for a long time when I was younger, I placed too much importance on it.

As we all know, there is a lot more to terminal ballistics than energy. And if you were to dig through my posts deep enough, you'll find that I have emphasized before that KE is a good measure of the ability to do work. I've said more than once and almost verbatim that a higher KE allows a bullet to be either driven deeper, expanded wider or a combination of the two.

This concept does not elude me.

However, back to the 100 ft/lbs in .02 ft:

Quoted from the site you linked for the equations:

Even though the application of conservation of energy to a falling object allows us to predict its impact velocity and kinetic energy, we cannot predict its impact force without knowing how far it travels after impact.

Just as I said, we cannot know the force if we don't know the time (or velocity). We have distance and KE, but we need time (or velocity from which to calculate time) since force is a product of time, distance and mass or, more simply, acceleration (or deceleration) and mass.

That site also does not show us how to calculate the force applied by an energy exerting object that travels a certain distance but does not stop in that distance. I'll be content if you can solve for it as I mentioned earlier, or if you can point me to somewhere where I can, because I've been looking and had no success in coming up with any formula other than the one I derived using another for conservation of energy.

Until then, I maintain that using the standard force=time/distance*mass tells us that a bullet that deposits that energy in less time will produce greater force. Hence the 9mm round that depostis 100 ft/lbs over .02 ft in 17 microseconds exerts greater force on the target than the .45 ACP that deposits the same 100 ft/lbs in 26 Microseconds.

Noteworthy is that the difference in force between the 9mm and .45 loads is proportionate to the difference in momentum (after the energy loss).

I'm all ears for whoever can explain how something else mitigates the difference in force I came up with when the energy transfer occurs in the same distance over different times. I'm not being a smart@$$; I really would like to know if there's something I didn't factor in that will show both of those loads to produce 5,000 pounds of force, regardless of their different velocities and resulting different amount of time spent in the target delivering the energy.

It did strike me as quite a coincidence that the velocity loss of each was so close to shed 100 ft/lbs, though I didn't plan it that way; I just picked two common, standard loads.

No and no. No, it's not "Courtney's theory". No, it's not flawed.

So creating examples with inelastic collisions is only flawed if I do it?

JohnKSa
September 17, 2011, 12:45 AM
The website says:we cannot predict its impact force without knowing how far it travels after impact.But, of course we can if we DO know how far it travels after impact.

So with kinetic energy and penetration (how far it travels after impact) you can calculate impact force.We have distance and KE,Penetration distance and KE is enough. I gave you the equation, Courtney uses it, I gave you a link to a website that explains it.So creating examples with inelastic collisions is only flawed if I do it?Courtney's examples do not make any unjustified assumptions.

Your examples assumed that all the energy of the projectile was turned into acceleration of the target. That doesn't happen in the real world and therefore it's not surprising that your numbers appear to be unrealistic. (Assuming the calculations are correct--I'm not going to check them because whether they're correct or not the assumptions you've made will mean that your interpretation of the results will be totally unrealistic and therefore confusing to you.)force is a product of time, distance and mass or, more simply, acceleration (or deceleration) and mass.Kinetic energy is also a function of time, distance and mass, and can be expressed in terms of acceleration and/or deceleration as well. I gave you the relationships in an earlier post and if you don't believe me you can verify them elsewhere on the internet.

The units of Force are mass x distance / time / time
Mass, distance and time

The units of Kinetic energy are mass x (distance / time) x (distance / time)
Also mass distance and time

If you divide the units of Kinetic energy by distance you have the same units as Force.

Or, said another way, if you multiply the units of Force times distance you have teh same units as Kinetic energy.

KE = F x D

F = KE / D

http://www.school-for-champions.com/science/work_energy.htm
"Work is force times distance
The definition of work is that it equals force times the distance traveled while that force is being applied or

W = Fd"

"Work is kinetic energy"

http://hyperphysics.phy-astr.gsu.edu/hbase/work.html
"Average impact force x distance traveled = change in kinetic energy"

http://galileo.phys.virginia.edu/classes/109N/lectures/momentum.html
"work = force x distance"

http://www.ftexploring.com/energy/PE-to-KE.html
"Kinetic energy was converted to mechanical work (force acting through a distance"

http://www.lightandmatter.com/html_books/lm/ch13/ch13.html
"W = Fd"
"The change in kinetic energy associated with the motion of an object's center of mass is related to the total force acting on it and to the distance traveled by its center of mass "

http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/forces/kineticenergyrev1.shtml
"work done (joule, J) = force (newton, N) × distance (metre, m)"

http://www.livephysics.com/tools/classical-mechanics/solve-problem-related-to-impact-force-from-falling-object.html

"Average impact force x Distance traveled = Change in kinetic energy"

MachIVshooter
September 17, 2011, 01:45 AM
Yeah, nevermind. While you were writing that, I went back over my figures and reminded myself why you don't do that stuff when you're exhausted.

I made a couple of errors in bullet velocities because I didn't write them down, and that accounts for the discrepancies I had. It all adds up now.

This bit of confusion stems from never trying to equate pound force with bullets, because I was never trying to accelerate an object I was shooting at, so the number seems relatively useless. And it really is, since you can't quantify what that pound force becomes after impact. There is no breakdown for what percentage of it will expand a bullet, what percentage will damage the target, what percentage will move the target, etc., so it's purely academic.

The reason I questioned Courtney's figure with such ferocity is that, being someone who has a great deal of experience with applied force in my occupation and who has fired hundreds of thousands of rounds over the years, it seemed erroneous that something like a bullet could generate such force, yet barely be able to move something like a block of wood weighing only a few pounds. And honestly, it still doesn't seem right when we consider that a .22 LR can produce ~140 ft/lbs and stop only an inch or so (making ~1,650 pound force) into a bowling pin that weighs maybe 3 1/2 pounds, yet cannot drive that pin off of a table. I know that force is used up somewhere, but I'm sure most would agree that it seems something making enough force to accelerate a 1,650 pound mass to 32 FPS in one second should be able to move that damn pin off the table!

It would be interesting if we could find a sensitive enough accelerometer to attach to said bowling pin and see what it's accelertion is during the few microseconds the bullet is applying the force.

Thank you, though, for those sites. They'll be useful in the future, because the long hand of this stuff takes forever and, as I proved and ended up with egg on my face, leaves room for error.

winfried
September 17, 2011, 09:59 AM
Hi all, I do not have the time to read all this, but I spent my time working with the problem.
Have a look at the pictures, pressure is indicated by the "blow-out" near the wound channel.

Mechanical damage as well as hydro shock can be observed far from the bullet path.

Kinetic energy is the potential t o do damage, the deposited energy is an indicator of the damage.

As far a force (or power some of us will call it), a .223 will penetrate 100 to 150mm typically in a gelatine block causing much damage without penetration. A similar .22 bullet of much lower velocity will penetrate the gelatine block with ease. For those who understand, no explanation is needed, for those who do not understand, no explanation is possible.

One more thing, gelatine tests giving a comparable performance for different bullets, but are never an indication what will happen in a body.

Regards

Mike1234567
September 17, 2011, 10:33 AM
Nice post, winfried. Do you have more visuals? A picture is worth a 1000 words when trying to explain and prove something.:)

MachIVshooter
September 17, 2011, 11:34 AM
Mechanical damage as well as hydro shock can be observed far from the bullet path.

It most certainly can, and none of that is in question. We know that bullets passing through flesh create damage both by contacting the tissue directly and by creating pressure that in turn creates a cavity, and the damage caused by the cavity is a result of the tissue's ability or inability to stretch that far. Small temporary cavity in elastic tissue=a little bruising, while large temporary cavity through inelastic tissue=horrific damage.

However.......this thread is about the remote effects or lack thereof with a ballistic pressure wave that propagates through the vascular system in a living creature and, as much fun as shooting chunks of meat is, it tells us nothing of those effects.

Mr. Courtney is hell-bent on proving that a ballistic pressure wave can cause remote cerebrovascular damage that accelerates incapacitation, but there is a great deal of distance between finding small vascular hemorrhages in the brains of some deer shot with high velocity rifle bullets in an uncontrolled field experiment and proving that a service caliber handgun can cause neurological incapacitiation of a human with remote BPW.

I believe (and I think the general concensus at this point concurs) that 1)it is going to be exceedingly difficult to isolate the effects of the BPW from all the other effects of being shot in a place where the BPW is close enough to a major vessel to even be a factor and 2) That the effect or lack of effect the BPW has really isn't going to change the fact that service caliber handgun effectiveness is dependent on penetration and shot placement.

As was pointed out earlier:

Let's take hydrostatic shock theory first. In order to generate the most possible hydrostatic pressure in the target, you want to put the shot into areas of the body that have the most fluids, organs, etc, center of mass. That way you get enough of a pressure wave to travel through the bloodstream, damage the brain, and incapacitate the target.

Now for the internal bleeding/organ failure theory. You want to put your shot in the areas of the body to do enough damage to the internal organs as possible, in order to cause bleeding severe and rapid enough that the target loses the ability to function and is thusly incapacitated.

So in short, if you believe in the hydrostatic shock theory, you aim center of mass.

And if you don't believe in the hydrostatic shock theory... you aim center of mass.

PowerG
September 17, 2011, 02:01 PM
That pretty well sums it up, MachIV. Common sense would indicate there could be effects from the pressure wave, but there is a big difference between the most common self-defense handgun calibers and hunting rifles, and it's obvious that many shootings have taken place where the shock presupposed by proponents of that have obviously had little or no effect on the bad guys. So for me, I'll put more trust in COM bullet placement, and if the shock wave ends the encounter faster, so much the better...but I know for a fact that permanent cavities through vital organs tend to work rather well.

rhodco
September 17, 2011, 07:48 PM
Gee, with all the physicists and scientists in this one gun forum we should be able to solve all the world's problems now. ;)

All I know about this subject is what I saw when shooting a metal newspaper vending machine we found in the woods. My 9mm 124gr +P Speer JHP @ 1200fps made an impressive dimple from about 11 yards away. But, my .45ACP 230gr FMJ @810fps punched all the way through from the same distance. Several times from different angles we proved to ourselves that the .45ACP was doing much more damage with each shot than the 9mm could.

Now I know what to use if I'm ever attacked by a metal newspaper box.:evil:

SN13
September 17, 2011, 11:08 PM
I'd imagine that "Hydrostatic shock" happens at different velocities for different calibers.

Because bigger bullets displace more tissue per inch of penetration, so the tissue would have to move faster to get out of the way for two bullets of different caliber but identical speed.

JohnKSa
September 17, 2011, 11:24 PM
I would like to publicly apologize to MachIVshooter for treating him less than respectfully on this thread.

Clearly he has a strong interest in this topic and equally obviously he's willing to spend time and effort learning about the physics and mathematics involved, all of which is commendable.

It was wrong of me to respond harshly instead of taking the opportunity to be more constructive in how I addressed his comments. I will do better in the future.That the effect or lack of effect the BPW has really isn't going to change the fact that service caliber handgun effectiveness is dependent on penetration and shot placement.I think this is a reasonable statement. At this point it seems that BPW might provide a way to shade the odds a bit in one's favor by choosing calibers that the Courtney's research/calculations indicate create BPW magnitudes sufficient to have a good chance of causing significant neurological effects.

Assuming, of course, that such a choice doesn't result in tradeoffs that are unacceptable or unwise for a particular shooter.

In other words, pick something out of the service pistol/self-defense caliber class with adequate penetration, that you can shoot well, load it with premium self-defense expanding ammunition, aim for the center of mass and shoot as many times as it takes to cause cessation of hostilities. Sound familiar? ;)

I do not intend that statement to belittle or dismiss the research and experimentation the Courtneys have done. I believe their research is helpful because it explains effects that are commonly observed but not well-explained and because it expands our knowledge and understanding of terminal ballistics. I look forward to more research and experimentation on this topic as I hope the entire firearm community does.

There is certainly a lot that we still don't understand about terminal ballistics and it's unfortunate that there are strong and well-respected voices in the established community of terminal ballistics researchers that seem to be willing to speak out scathingly against anything that disagrees in the slightest respect with their pet theories and published ideas regardless of whether or not it seems to have a good basis in fact & science. We need to be careful to balance our skepticism with a level of open-mindedness that allows us to at least examine and evaluate new ideas objectively as opposed to dismissing them out of hand as some are wont to do.

Panzercat
September 17, 2011, 11:57 PM
Is this thread still going on?

http://i262.photobucket.com/albums/ii110/ozzallos/pic-nosler.jpg

winfried
September 18, 2011, 02:48 AM
Hi, a 14 year old boy had driving a tractor when a .22 rifle discharged accidently. The bullet graced the neck only. All important blood vessels were missed.
The boy was stitched up and kept for three days observation. He was sent home but died 4 days later. Autopsy showed that microscopic bleeding in part of the brain, as the result of hydro shock was the cause of death.

Furthermore you people have the most complete study of woundballistics in the Library of Congrees. The book is called

winfried
September 18, 2011, 02:55 AM
Sorry, the book is called WOUND BALLISTICS by Maj Beyer. To produce this book today, would probably cost US$ 20 Million. In it every aspect under discussionhere is dealt with.

Pressure waves, damage of nerves far from wound channel, broken bones as a result of a bullet passing nearby.

Furthermore when somebody talks about shot placement and center of mass, how do you define center of mass? If you mean the upper torso, there is not much chance of disabling somebody. Any shot below the lungs will be instantly disabling.

Regards

winfried
September 18, 2011, 03:14 AM
I agree with the statement that researchers often do have a pet theory and fail to look right or left. Also for the researcher who knows, he can prove today one fact and tomorrow the opposite fact without being dishonest.
For instance, it is easy to prove that a .223 bullet (soft point or FMJ makes no difference) will penetrate at least 10mm mild steel plate. By making a different arrangment the .223 will only pnetrate 3mm mild steel.
Or a 8gram 9mm FMJ fired from a 3" 357 will not realy make a dent, but a small mark on a 10mm steel plate. Then with different arrangement the latter bullet will penetrate 8mm of mild steel.
How is that for confusion? Easy to prove by anyone.
However, reading other peoples research papers, observing autopsies and filling the gap with own research, there is not really a mystery to wound ballistics.
In the USA there are two problems, one is the imperial system in use and the other is the nonsense brought about by the 1904 Thompson Lagarde tests, then quoted wrongly by somebody and then Hatcher developing the idiotic RSP formulae, which is easy to understand but as wrong as can be.

Regards

winfried
September 18, 2011, 03:18 AM
"About 03h we received a radio message that a bushman tracker had returned to one of the camps with a chest shot from an AK and wuld be brought into Runtu hospital by helicopter. On notification that the patient had arrived and was in theater, we found him standing there smoking a cigarette with his rifle over the shoulder. He had a wound on the left chest in front and in the back. We took x-rays and found indeed that it was through and through wound. We cleaned and closed the wound and kept him for a week in case an infection would come to pass. This did not happen, but during that time we found out, that the bushman was wounded early morning the previous day. He tracked the terrorist during the day for about 12 hours. He said he could have shot his prey a few times during the day, but he wanted to shoot him in the abdomen so that his opponent would die painfully and slowly. Just before sundown he could get his shot placed and then walked back another eight hours back to base."

JohnKSa
September 18, 2011, 04:22 AM
Winfried,

Is this the book you refer to?

WOUND BALLISTICS

Editor in Chief: Colonel JAMES BOYD COATES, Jr., MC
Editor for Wound Ballistics: Major JAMES C. BEYER, MC

http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/default.htm

Loosedhorse
September 18, 2011, 07:25 AM
It was wrong of me to respond harshly instead of taking the opportunity to be more constructive in how I addressed his comments. I will do better in the future.I recognize the correctness of your words here, and admire them. I will try to take them as my example.well-respected voices in the established community of terminal ballistics researchers that seem to be willing to speak out scathingly against anything that disagrees in the slightest respect with their pet theoriesAgreed. I believe the biggest problem that has caused is the poor example it sets. It gives the impression that the way to "discuss" such issues is to dismiss the other's theory, and "explain" that the other is an idiot.

No. What I have tried to point out is that we don't know more than we know. We do not know enough to say that the Courtneys' BPW-causes-incapacitation theory is true...and so similarly, we don't know enough to say it's false. There often seems confusion on this point: lack of proof that something occurs is NOT the same as proof that it does not occur. In fact, it is rather common for scientific theories to remain suspended for years between proof and disproof*.

I believe that one reason that some have claimed that the theory is already proved false is the reliance on demonstrably false statements (about anatomy or physics), and I've tried to point those out, as IMHO they would present the most serious blocks to understanding. And to the extent that I have done that, I trust I have contributed.

I have also made less helpful comments. I will continue, instead, in the spirit JohnKSa suggests.

*In theory, an idea can never be "proved true," only proved false. However, some theories (evolution is a good example) are so firmly established by evidence that there is no practical possibility they will ever be disproven, although the theory may need its details modified from time to time.

MachIVshooter
September 18, 2011, 10:49 AM
I would like to publicly apologize to MachIVshooter for treating him less than respectfully on this thread.

Thank you, John.

. In the USA there are two problems, one is the imperial system in use

What's wrong with imperial? All the same measurements exist, just denoted differently. if you prefer Nm and Kw to Lb.Ft. and Bhp, that's your perogative, but it doesn't mean there's anything wrong with the latter.

In my field, I use both pretty much daily and can convert most units back and forth easily. That said, SAE units have their advantages, too. *F being finer divisions than *C, for example. More precision with integers.

I think what we're most comfortable with is what we grew up on, but that doesn't make another system inferior

brickeyee
September 18, 2011, 02:35 PM
Clearly he has a strong interest in this topic and equally obviously he's willing to spend time and effort learning about the physics and mathematics involved, all of which is commendable.
Maybe when he learns to use the correct units he might be worth listening to.

Pasteur
September 19, 2011, 08:42 AM
there is a great deal of distance between finding small vascular hemorrhages in the brains of some deer shot with high velocity rifle bullets in an uncontrolled field experiment and proving that a service caliber handgun can cause neurological incapacitation of a human with remote BPW.

Yes, of course, but this is one paper among many. Seldom does a single paper address all facets of a complex topic. The fact is that remote brain injury (from shots to the chest) was predicted before it was observed based on incapacitation and related data. Other papers provide evidence that:

1) Humans shot in the chest with handguns experience cerebrovascular damage.
2) Other factors being equal, deer shot in the chest with handgun bullets with higher ballistic pressure waves are incapacitated more quickly, on average, than deer shot in the chest with handgun bullets with smaller ballistic pressure waves.
3) Pigs shot in the thigh with projectiles transferring pistol levels of energy display depressed EEG readings that would probably correspond with incapacitation if they were not anesthetized.
4) Pigs shot in the thigh with projectiles transferring pistol levels of energy display transfer of pressure from the bullet impact to the brain (measured with pressure transducers) and neurological injury in both peripheral nerves and the central nervous system.
5) Dogs shot in the thigh with pistol levels of energy experience traumatic brain injuries. Greater energy transfer correlated with greater remote brain injury.
6) Pigs shot in the chest with rifle bullets stopped by body armor (no penetration) experience immediately depressed EEG readings that would probably correspond to incapacitation if they were not anesthetized. Pistol levels of energy are transferred to tissues behind the armor, and the degree of EEG suppression corresponds with the amount of energy transferred to thoracic tissues behind the armor.
7) Epidemiological data shows the probability of rapid incapacitation in humans is highly correlated with peak ballistic pressure wave magnitude.
8) The average incapacitation time in goats is highly correlated with peak ballistic pressure wave magnitude from pistol bullets.
9) Experiments have shown immediate incapacitation in 10 lb mammals exposed to ballistic pressure waves generated by handgun bullets without any penetration.
10) Blast pressure waves can be transmitted to the brain via the thorax resulting in brain injury.
11) Fish can be killed by bullets passing near them in the water without hitting them.
12) Studies in goats show projectile impacts to the thigh generating similar lethal outcomes to explosives taped to the thigh.
13) Brain haemorrhages have been observed in cape buffalo shot in the chest and correlated to immediate incapacitation.

As the recent paper in Neurosurgery pointed out, the totality of the evidence is compelling and hydrostatic shock is “now well established in a broad body of scientific literature.”

I should also mention that I do not believe the BPW mechanism suggests the center of mass as the proper point of aim. On the contrary, I believe the implication is that the center of the chest is the optimum point of aim, if available.

MachIVshooter
September 19, 2011, 11:04 AM
The fact is that remote brain injury (from shots to the chest) was predicted before it was observed based on incapacitation and related data.

I submit that one can find evidence to support almost any theory. It's been demonstrated many times. The problem is, when there is a pet theory, it seems that evidence to the contrary is often dicarded. This is human nature; We want to believe something is true, we try to prove it to ourselves and everyone else.

I am not saying this theory is entirely false, but there seems to be much more evidence discrediting than supporting. For example, for each of these animals shot in studies that have "shown immediate incapacitation from remote neurological damage" or however it is that you care to put it, there are countless hunters who have placed a high powered rifle bullet right in the boiler room and watched the animal take off like a shot (pun intended) and run some distance. I'm among that group.

Since you have cited these studies, it is incumbent on you to provide links to them if we are to believe your claims. Until then, I'm going with:

1) Humans shot in the chest with handguns experience cerebrovascular damage.

This statement is probably the worst, since it states an absolute; A single case to the contrary makes this claim false.

2) Other factors being equal, deer shot in the chest with handgun bullets with higher ballistic pressure waves are incapacitated more quickly, on average, than deer shot in the chest with handgun bullets with smaller ballistic pressure waves.

How did the test mitigate the fact that the higher energy projectiles tend to make a larger bullet penetrate deeper, resulting in greater tissue damage thus more rapid incapacitation?

3) Pigs shot in the thigh with projectiles transferring pistol levels of energy display depressed EEG readings that would probably correspond with incapacitation if they were not anesthetized.

"Probably". I love that one, because it pretty much removes any burden of proof. Nonetheless, I'd like to review this test in it's entirety.

4) Pigs shot in the thigh with projectiles transferring pistol levels of energy display transfer of pressure from the bullet impact to the brain (measured with pressure transducers) and neurological injury in both peripheral nerves and the central nervous system.

"transferring pistol levels of energy" leaves a lot of room for skewing. There are many handguns that produce much more energy than small bore rifles. That does not mean the terminal ballistics are the same. I demonstrated exactly that earlier in the thread with 10mm vs. .17 Rem.

5) Dogs shot in the thigh with pistol levels of energy experience traumatic brain injuries. Greater energy transfer correlated with greater remote brain injury.

Once again, I would like to see the test.

6) Pigs shot in the chest with rifle bullets stopped by body armor (no penetration) experience immediately depressed EEG readings that would probably correspond to incapacitation if they were not anesthetized. Pistol levels of energy are transferred to tissues behind the armor, and the degree of EEG suppression corresponds with the amount of energy transferred to thoracic tissues behind the armor.

There's that probably thing again.

7) Epidemiological data shows the probability of rapid incapacitation in humans is highly correlated with peak ballistic pressure wave magnitude.

And peak ballistic pressure wave, I suspect, is highly correlated with smaller bullets expanding less and/or having relatively shallow penetration, and larger bullets being expanded wider and driven deeper with that greater energy.

8) The average incapacitation time in goats is highly correlated with peak ballistic pressure wave magnitude from pistol bullets.

See above.

9) Experiments have shown immediate incapacitation in 10 lb mammals exposed to ballistic pressure waves generated by handgun bullets without any penetration.

Not surprised. That'd be like a human taking a cannonball.

10) Blast pressure waves can be transmitted to the brain via the thorax resulting in brain injury.

How was the blast pressure wave isolated to the thorax? Seems that would be virtually impossible to do.

11) Fish can be killed by bullets passing near them in the water without hitting them.

Probably. But then again, I've shot at fish before with .22 LR, 9x19mm and ..223, and none of the ones that weren't hit came floating up.

12) Studies in goats show projectile impacts to the thigh generating similar lethal outcomes to explosives taped to the thigh.

As is covered countless times in this forum, lethal and incapacitating have much separation. Many lethal injuries are not immediately incapacitation ones.

13) Brain haemorrhages have been observed in cape buffalo shot in the chest and correlated to immediate incapacitation.

I'd really like to see that one, since cape buffalo are well known for charging after being shot.


I should also mention that I do not believe the BPW mechanism suggests the center of mass as the proper point of aim. On the contrary, I believe the implication is that the center of the chest is the optimum point of aim, if available.

Funny, since COM targets tend to put the highest value in pretty much the same place:

http://www.dayattherange.com/wp-content/uploads/2009/03/rb9target-2.jpg

http://2.bp.blogspot.com/_wqnOMXc__lg/SHKSxnWv7PI/AAAAAAAAAL4/c-DqGtswcVM/s320/AC-002_01.jpg

http://www.taskforcetargets.com/images/full/target_sil_03.jpg

http://alcotarget.com/images/osb/Tq-16gry.gif

Perhaps not as high as you're thinking, but definitely higher than the middle of the torso.

winfried
September 19, 2011, 02:40 PM
Without trying to be difficult, can you explain how a slug foot is derived, so far no one could explain this to me.

Thank you

Winfried

winfried
September 19, 2011, 02:42 PM
Hi John, yes this is the book. I have a copy with my nickname embossed on the cover. Only for serious study.

Regards

winfried
September 19, 2011, 02:56 PM
You can shoot somebody in the chest, hit the lungs, in which no, and I repeat absolutely no pain is felt. I have quite some cases on record of this and I have cases where an abdominal shot is instantly disabling.
Furthermore, at handgun velocities, 50 to 80ms are needed (or lost) to penetrate skin. Then comes very soft ribcage, if bullet has not expanded when passing the ribs, no bullet expansion takes place in the lungs, that I can absolutely swear by.
Placing a shot in the abdomen has an instantly paralyzing effect like getting a proper kick to the testicles. If anybody tells me he can still function with a full proper kick in the testicle, he either lies, has never been kicked or he is abnormal.
In one case, one of two friends was shot in the abdomen with .38Spc.RN, the other was shot through the chest whereby the heart was nicked. The one withe the gut shot collapsed and was unable to do anything.The one with the chest shot made the one with the gut shot comfortable, made a statement, after about an hour, he had to sit down and died shortly afterwards.
For the record, the one with the gut shot had a miserable life for a long time, drains from the side hanging out, lots of anti-biotic, but he made it.

Regards

MachIVshooter
September 19, 2011, 04:18 PM
Without trying to be difficult, can you explain how a slug foot is derived, so far no one could explain this to me.

The pound force is the force required to accelerate 1 lb at 32.174049 FPS per second (or 32.174049 lbs @ 1 FPS per seond), defined by normal earth gravity (same as Nm).

The slug is just a 32.174049 (32.2) pound weight.

http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/slug.html

Odd Job
September 19, 2011, 04:27 PM
Placing a shot in the abdomen has an instantly paralyzing effect like getting a proper kick to the testicles.

You may have anecdotes that indicate this, but there are other anecdotes that indicate this is certainly not always the case.
In 2004 as I was leaving work at a London Hospital, there was a drive-by shooting right outside the Accident and Emergency department. I was on the upper parking deck and I heard the shots and saw the gunman getting away on a motorcycle (riding pillion).

Two people were hit. One was an unintended target, a young woman who sustained a perforating gunshot wound to the lower leg. The intended target was an adult male who took a shot through the abdomen, involving the liver.
Both individuals ran immediately for cover into the hospital where they were routed directly to the resus bay. I guess if you are going to get shot, it's best to let it happen outside the A&E.
The guy with the liver injury was first managed by attempted interventional radiology to coil a liver bleeder. There were other complications and the patient ended up having a laparotomy.
Both of these victims survived.
I checked the male's clothing and he had a perforated jacket sleeve also. Three or four shots were fired and 9mm cases were left on the road (I stopped a bus from running over one of them).
If I had come out of the entrance just ten seconds earlier, I would have seen the shooting directly.

Vern Humphrey
September 19, 2011, 05:14 PM
Quote:
Placing a shot in the abdomen has an instantly paralyzing effect like getting a proper kick to the testicles.

You may have anecdotes that indicate this, but there are other anecdotes that indicate this is certainly not always the case.
I have seen men shot about anywhere you can imagine (albeit with FMJ, not expanding projectiles.) Abdominal wounds, while they can be quite serious, depending on what organs are involved, will usually not stop a man.

I have also seen game animals -- such as white tail deer -- that were gut-shot, and have tracked at least one for more than a mile.

So I would say it is rarely the case that an abdominal would will have an instantly paralyzing effect -- and when it does, I suspect it is more a psychological effect than a physiological one.

brickeyee
September 20, 2011, 01:12 PM
Without trying to be difficult, can you explain how a slug foot is derived, so far no one could explain this to me.

Thank you

Winfried

It is as simple as the difference between mass and weight.

English vernacular does not deal with mass, it deal with weight.

To have a consistent set of units for scientific work we need a unit of mass.

By dividing weight (a force) by the acceleration that created it (gravity) we have a unit of mass (F=ma, so m=F/a).
This unit is (somewhat facetiously) called a slug.

Now the regular expressions for energy (like 1/2 * m * v^2) work consistently,.

The metric system as commonly used has the same problem.

No one states their weight in Newtons (the unit of force) but uses kilograms (the unit of mass).

Your weight depends on gravity (acceleration), your mass is constant.

If your weight is 200 pounds on earth, your mass is ~6.2 slugs.

Your weight on the moon would be about 33 pounds, but your mass would still be ~6.2 slugs.

JohnKSa
September 21, 2011, 12:22 AM
I am not saying this theory is entirely false, but there seems to be much more evidence discrediting than supporting. For example, for each of these animals shot in studies that have "shown immediate incapacitation from remote neurological damage" or however it is that you care to put it, there are countless hunters who have placed a high powered rifle bullet right in the boiler room and watched the animal take off like a shot (pun intended) and run some distance. I'm among that group.The example you give and others like it won't discredit the theory because there is no claim made that BPW is ALWAYS an incapacitating effect, even when using a round that generates a relatively high BPW.

The material is fairly clear that you can increase the chances of BPW being an incapacitating factor but that's about it. No one is selling BPW as a 100% reliable mechanism for incapacitation. Which means that finding a situation where BPW didn't incapacitate doesn't cast any doubt on the theory at all.
"Probably". I love that one, because it pretty much removes any burden of proof.Regardless of whether the "probably" is true or not, the EEG does show effects. That's a result, in and of itself that provides evidence of remote neurological effects due to bullet strikes."transferring pistol levels of energy" leaves a lot of room for skewing.You have to understand the context. The claim has been widely made that remote effects are a non-issue in handgun incapacitation. Therefore, showing that remote effect ARE an issue at "pistol levels of energy" is a significant result. While your point is accurate, the claim being addressed by the assertion is so sweeping that a carefully qualified energy level is not necessary to demonstrate that a contradiction exists. Not surprised. That'd be like a human taking a cannonball.The key phrase in the claim was "without penetration". The bullet did not touch the test subject. In other words, any effects due to actual penetration of the bullet were excluded from having an effect on the test subject. And yet some of the test subjects were incapacitated and showed evidence of neurological trauma/damage.

At this point, I believe that there is enough evidence from enough different sources demonstrating remote effects of BPW that it is essentially impossible to deny that BPW can cause remote effects leading to incapacitation in some cases. Further, based on the evidence I've seen from numerous sources, it is not possible to effectively support an assertion that BPW can be completely excluded as a significant effect even if we limit things to handgun incapacitation. In other words, the theoretical part of the battle has been won by the BPW researchers. They have enough evidence to prove it exists and that it can be a factor even at handgun energy levels.

Which means that the focus of the BPW debate will now swing toward how much of a practical effect it has, how probable that effect is, and what can be done from a practical perspective to offer the best chance to bring it into play in the real world. That may actually be a much tougher nut to crack.

MachIVshooter
September 21, 2011, 01:44 PM
The example you give and others like it won't discredit the theory because there is no claim made that BPW is ALWAYS an incapacitating effect, even when using a round that generates a relatively high BPW.

The material is fairly clear that you can increase the chances of BPW being an incapacitating factor but that's about it. No one is selling BPW as a 100% reliable mechanism for incapacitation. Which means that finding a situation where BPW didn't incapacitate doesn't cast any doubt on the theory at all.

It does seem that it is the goal of some, though, with statements like

1) Humans shot in the chest with handguns experience cerebrovascular damage.

No, the term "incapacitation" doesn't appear here, but seems implied. And, as I said earlier, stated as an absolute, this claim is easily made false by just one example of it not occuring.

Regardless of whether the "probably" is true or not, the EEG does show effects. That's a result, in and of itself that provides evidence of remote neurological effects due to bullet strikes.

It does show evidence of remote effects, and as I've been saying all along, I don't think any of us are questioning that there can be effects, but rather the magnitude. Kinda like seismic activity; It has to get to a certain level to be felt, and far more to cause damage.

showing that remote effect ARE an issue at "pistol levels of energy" is a significant result.

I guess if we're hung up on the notion that energy is the only factor. But I don't think anyone can argue that velocity is not a significant factor in wounding ability. As well, "Pistol levels of energy" has quite a bit of ambiguity these days, with certain handgun rounds making more energy than a .308. This thread seems to center largely on whether these effects are present with service caliber handguns, and that is not defined here.

The key phrase in the claim was "without penetration". The bullet did not touch the test subject. In other words, any effects due to actual penetration of the bullet were excluded from having an effect on the test subject. And yet some of the test subjects were incapacitated and showed evidence of neurological trauma/damage.

I know, and I understood that. I've caught the bits Courtney has mentioned about chest wall acceleration, etc. from explosive shockwaves, too. My point was that this test used a 10 pound animal. It's about scale, so even assuming a service caliber round like .45 ACP ball ammo, if scaled up to man size (like the 70 Kilo weight stipulated in the army tests you linked, which 154 Lbs. is small by current standards), you're talking about a half pound projectile developing 6,000 ft/lbs. I'm sure that would cause considerable damage, even if stopped by a vest.

A service caliber bullet that can kill a man will absolutely destroy a rabbit sized animal, but have virtually no effect at all on something the size of an elephant. That is my point.

At this point, I believe that there is enough evidence from enough different sources demonstrating remote effects of BPW that it is essentially impossible to deny that BPW can cause remote effects leading to incapacitation in some cases.

I agree.

That said, I still would like to know more about how the BPW effect was isolated from everything else. Were they able to somehow demonstrate that the local injury absolutely could not have incapacitated that quickly through blood loss/damaged vital organs? And, if so, how do we isolate the neurological effects of the BPW from the psychological effects of major trauma?

It is just my nature to always be skeptical, always question. Sometimes it may come across as hostile or accusatory, and for that I am sorry. But there are still many questions to be answered, specifically correlation vs. causation. Things like the EEG results are a step in the right direction here, but IMO, are a long way from concluding that there would have been incapacitiation resulting from BPW-caused remote neurological damage.

KenB22
September 21, 2011, 11:39 PM
We can argue about this for days. What do the people in the industry or who put their lives on the line every day think of this theory? My research suggests the IWBA, FBI etc have no use for this theory. If they don't use it as a factor in their choice of ammo, why should we?

JohnKSa
September 22, 2011, 12:43 AM
No, the term "incapacitation" doesn't appear here, but seems implied. And, as I said earlier, stated as an absolute, this claim is easily made false by just one example of it not occuring.It is if he meant to say "All humans shot in the chest...". Based on the contents of his papers and his other comments, I don't believe that would be an accurate restatement of the sentence.I guess if we're hung up on the notion that energy is the only factor.Energy provides a convenient method for calculating force and therefore pressure using easily measured data (penetration). One could do the same calculations with momentum, but then one would need to know the deceleration time which would be harder to measure. So it's not that energy is the only factor, it just happens to be convenient because of the information available.But I don't think anyone can argue that velocity is not a significant factor in wounding ability.It's not possible to separate velocity from kinetic energy, or from momentum. It would be accurate to call them 3 sides of the coin--if there were such a thing as a 3-sided coin, that is. :D

You can calculate the applied force using either kinetic energy and penetration, or from momentum and deceleration time, or, directly from velocity, penetration distance and deceleration time using the F=ma equation. The results are the same regardless of which route you choose to take. It's just that in this case it's easy to measure penetration and energy while measuring the deceleration time would be much more complicated.This thread seems to center largely on whether these effects are present with service caliber handguns, and that is not defined here.At least one of the papers linked on this thread contains a more careful quantification of the energy levels and the range does contain at least some of the service pistol calibers.That said, I still would like to know more about how the BPW effect was isolated from everything else. Were they able to somehow demonstrate that the local injury absolutely could not have incapacitated that quickly through blood loss/damaged vital organs?Yes, the tests done that coupled the BPW to the test subject via water and didn't involve any penetrating injury to the test subject isolate the BPW from everything else by eliminating all factors related to penetration injuries.

http://www.ballisticstestinggroup.org/lotor.pdf

The test subject's heads were out of the water so the only method for inducing any incapacitative effects to the brain were by coupling the BPW through the water, into the body and then through the blood vessels to the brain.

The comments about the issues of scale are to the point, however, the test results are still very revealing because they do eliminate the confusion about whether the incapacitation was due to penetrating injury and also because the results (probability of incapacitation) tracked the calculated BPW figures very well. In other words, the tests weren't to claim that a particular loading that produced 3 out of 5 incapacitation results on the test subjects will also produce similar results in humans. The point was that the effect can exist in the absence of a penetrating wound and that the observed effect does correlate well with predicted BPW.It is just my nature to always be skeptical, always question.A reasonable approach, nothing wrong with that.If they don't use it as a factor in their choice of ammo, why should we?Since you asked, here's my take. ;)

I wouldn't consider trading a very predictable performance parameter, like penetration, for a probabilistic factor like BPW. BUT, if one were making a choice between two loadings that both meet all the criteria for penetration, shootability, etc. then one might as well choose the one that is predicted to provide the strongest BPW. It can't be any worse than flipping a coin.

Loosedhorse
September 22, 2011, 10:18 AM
Since you asked, here's my take.And here's mine: I'm not sure I need as much penetration as the FBI does.

The FBI went to its current recs after the Miami Shoot-out, specifically after one agent's 115 gr Silvertip 9mm (c. 1200 fps) fired from perhaps 10 yards penetrated an arm, a chest, collapsed a lung, severed a vital artery...but stopped an inch short of the heart. It is presumed that if the heart, rather than the artery, had been hit, all would have been different.

In moving to the 10 (temporarily), the FBI said of the 9:We are saying it is as good as a .38 Special, which has served us for a long time. It has severe limitations, which we are not willing to accept. It is woefully inadequate for shooting at people in cars, for example, and over half of our shootings involve vehicles. It is a marginally adequate wounding agent.
So, one reason for the emphasis penetration is that over half of their shootings involve vehicles.

Also: one of the enduring mysteries of Marshall and Sanow's "Stopping Power" data was the .32 ACP "old" Silvertip: 63% one-shot stops (same as .45 hardball) and 6.5 inch penetration? How's that possible?

Of course, one possible explanation is bad data. But unlike most of the calibers they looked at, the .32 ACP (even then) was not favored by uniformed police, so that the shootings for this round were weighted toward private citizens and undercover cops, who were thought not to be armed. How would these shootings be different (on average, not always) from uniformed police shootings?

Less dedicated attacker: didn't expect his victim was armed, more likely to stop or run if hit once
Closer range with fewer obstacles
More likely to have a frontal chest target
Others?

Even I am not happy with 6.5 inches of penetration (or 63%), but I'm not sure I should sneeze at 9.5. Nothing wrong with the FBIs minimums; I just remember that they were developed for the FBI with particular attention to THEIR typical shootings, and therefore their particular balance between under- and over-penetration.

And if I can get 9.5 or 10" of penetration plus a BIG (say, 700 ft-lb) energy dump; or 14" and a small one; well, I know which the FBI would choose. But I might choose differently. JMHO, YMMV.

2zulu1
September 22, 2011, 07:50 PM
It appears Dr Courtney is posting under the psuedonym of Pasteur.

In Courtney’s own words;


Scientific Evidence for “Hydrostatic Shock”

“Hydrostatic shock” expresses the idea that organs can be damaged by the pressure wave independently from direct contact with the penetrating projectile. If one interprets the "shock" in "hydrostatic shock" to refer to physiological effects rather than physical wave characteristics, the question of whether the pressure waves satisfy the definition of “shock wave” is unimportant. There is compelling scientific evidence supporting the ability of a ballistic pressure wave to create tissue damage and incapacitation in living targets.

Energy Transfer Required for Remote Neural Effects

Our own research (Courtney and Courtney) supports the conclusion that handgun levels of energy transfer can produce pressure waves leading to incapacitation and injury.[29][30][26][31][32] The work of Suneson et al. also suggests that remote neural effects can occur with levels of energy transfer possible with handguns (roughly 500 ft-lbs/ 700 joules).

Recommendations

The FBI recommends that loads intended for self-defense and law enforcement applications meet a minimum penetration requirement of 12” in ballistic gelatin.[8] Maximizing ballistic pressure wave effects requires transferring maximum energy in a penetration distance that meets this requirement. In addition, bullets that fragment and meet minimum penetration requirements generate higher pressure waves than bullets which do not fragment. Understanding the potential benefits of remote ballistic pressure wave effects leads us to favor loads with at least 500 ft-lbs of energy.



However, Duncan MacPherson discounts the enregy transfer statement by Courtney.


“. . . every now and then someone wants to analyze or think about a problem involving energy, and when they attempt to do this without really understanding energy or other thermodynamic concepts the result is unfortunate. One such problem is the analysis of any of the various aspects of terminal ballistics; some individuals with inadequate technical training and experience have unwisely and unproductively attempted to use energy concepts in the analysis of bullet impact and penetration in soft tissue. (Many others have simply assumed that energy is the dominant effect in Wound Trauma Incapacitation; this assumption is even more simplistic than the attempt to actually analyze the dynamics problem with energy relationships, and is no more successful).

Any attempt to derive the effect of bullet impact in tissue using energy relationships is ill advised and wrong because the problem cannot be analyzed that way and only someone without the requisite technical background would try. Many individuals who have not had technical training have nonetheless heard of Newton’s laws of motion, but most of them aren’t really familiar with these laws and would be surprised to learn Newton’s laws describe forces and momentum transfer, not energy relationships. The dynamic variable that is conserved in collisions is momentum; kinetic energy is not only not conserved in real collisions, but is transferred into thermal energy in a way that usually cannot be practically modeled. The energy in collisions can be traced, but usually only by solving the dynamics by other means and then determining the energy flow.



From Dr Gary Roberts;


"...I was a member of the Joint Service Wound Ballistic Integrated Product Team, the U.S. government study that gathered numerous experts from a variety of disciplines, including military and law enforcement end-users, trauma surgeons, aero ballisticians, weapon and munitions engineers, and other scientific specialists to conduct a 4 year, 6 million dollar study to determine what terminal performance assessment best reflected the actual findings noted in OCONUS combat the past few years. Courtney's "hydrostatic shock" was NOT found to be a valid or relevant factor. Likewise, I work at a large Level I trauma center and get to treat people who are shot in the face and jaws--guess what, NO remote CNS or other "hydrostatic shock" effects of the type Courtney espouses have occurred in ANY of these patients.

"...JSWB-IPT was initiated in 2002 and concluded in 2006. I should note that the joint USMC-FBI ammunition study of 2006 also found the same results. Oh...and the CTTSO/TSWG MURG program of 2007-2008 also made the same conclusions. Please think through this--the JSWB-IPT, FBI BRF, AFTE, and other organizations get to assess an extensive amount of post-shooting forensic data; the whole raison d'être of these independent, non-profit organizations is to interpret and disseminate information that will help LE and military personnel more safely and effectively perform their duties and missions. Why would they discount or ignore a potentially important incapacitation mechanism if there was any validity to it? I challenge you to read through all of the papers cited in Courtney's work and then make you own conclusions--everyone I know who has done just that has walked away utterly unconvinced of their merit."

Currently I am qualified on .45 ACP 1911 and 9 mm Glock; if I ever go back to LE Patrol duties, I'll likely carry a .40 S&W M&P. I don't really care that much about which one I am issued, as ALL the handgun service calibers work similarly.

During the early to mid 1980’s, like many people, I was duped by articles singing the praises of the .357 Mag 125 gr JHP. I carried a 4” 686 and a customized 3” M13 loaded with Fed 125 gr JHP. However, after going on active military duty and being in a position to test ammunition at the Letterman Army Institute of Research with Dr. Fackler, it became obvious that the .357 Magnum 125 gr JHP’s tended to have relatively shallow penetration, frequently fragmented with resultant decrease in permanent crush cavity, and had temporary cavities of insufficient size to contribute significantly to wounding. In addition, these loads had a large muzzle flash and blast, as well as a relatively harsh recoil which inhibited accuracy and re-engagement speed. As the FBI established a science based ammunition testing program, their research data also showed less than stellar performance from the lightweight .357 Mag loadings, including the 125 gr JHP’s. For those individuals who doubt evidence based research and prefer “street results”, the CHP, the largest agency to issue .357 Mag 125 gr JHP’s on the West Coast, clearly reports significantly better results in their officer involved shootings since switching to .40 S&W 180 gr JHP loadings, based on officer perception, objective crime scene measurements, as well as the physiological damage described in the relevant autopsy studies. The CHP used a variety of .357 Mag loads, depending upon what was available via the state contract. According to the published CHP test data from 1989-90, the .357 Magnum load used immediately prior to the CHP transition to .40 S&W was the Remington 125 gr JHP with an ave. MV of 1450 f/s from their duty revolvers. I first saw the data when it was presented during a wound ballistic conference I attended at the CHP Academy in the early 1990's; I heard it discussed again at a CHP Officer Involved Shootings Investigation Team meeting in November of 1997 at Vallejo, CA. The information reviewed the differences in ammunition terminal performance such as penetration depth, recovered bullet characteristics, tissue damage and other physiological measurements and physical evidence detailed during forensic analysis..."

Dr. Roberts is currently on staff at Stanford University Medical Center; this is a large teaching hospital and Level I Trauma center were he performs hospital dentistry and surgery. After completing his residency at Navy Hospital Oakland in 1989 while on active military duty, he studied at the Army Wound Ballistic Research Laboratory at the Letterman Army Institute of Research and became one of the first members of the International Wound Ballistic Association. Since then, he has been tasked with performing military, law enforcement, and privately funded independent wound ballistic testing and analysis. He remains a Navy Reserve officer and has recently served on the Joint Service Wound Ballistic IPT, as well as being a consultant to the Joint FBI-USMC munitions testing program and the TSWG MURG program. He is frequently asked to provide wound ballistic technical assistance to numerous U.S. and allied SOF units and organizations. In addition, he is a technical advisor to the Association of Firearms and Toolmark Examiners, as well as to a variety of Federal, State, and municipal law enforcement agencies. He has been a sworn Reserve Police Officer in the San Francisco Bay Area, where he now he serves in an LE training role.


Dr. Courtney (Pasteur) was not a part of the multi-million dollar research projects.

JohnKSa
September 23, 2011, 12:08 AM
However, Duncan MacPherson discounts the enregy transfer statement by Courtney.Yes, he does. I wonder if he's reconsidered that stance given the proof that is now available to support many of Courtney's claims.

Dunno what to say about Dr. Roberts' comments. Clearly remote effects from hydrostatic shock are well-established fact and have been for many decades. A quick perusal of Wound Ballistics by Coates & Beyer, published in the early 1960s shows that the studies done for the book demonstrated conclusively with photographic (high-speed X-Ray) that hydrostatic shock was capable of breaking bones that weren't struck by a projectile passing through nearby tissue.

GLOOB
September 23, 2011, 12:54 AM
Hydrostatic shock doesn't have to kill a person to have an effect.

If you poke a person in the right spot with 3 fingers, you can near instantly incapacitate or distract him for several seconds with ZERO permanent damage. Enough time to followup with some more lasting strikes.

If a bullet causes a greater temporary wound cavity, it would obviously have some greater effect than a bullet that makes the exact same wound channel with no cavitation. It might not increase mortality, but it might cause enough temporary neural disruption to change an attacker's attitude, when placed in the right spot.

pisc1024
September 23, 2011, 09:14 AM
12) Studies in goats show projectile impacts to the thigh generating similar lethal outcomes to explosives taped to the thigh.


You can't be serious about this statement. Please tell me you were just exaggerating, and that you were trying to make a point. To say that a GSW is in any way shape form or fashion is even close to high explosives going off on or near your body is in my mind stating that one has NO CLUE how explosives work. Further more that statement would suggest that you have obviously never done a study to back this up your self.
I would be very interested in these "studies" you speak of. And no, shoving fire crackers into the mouths of frogs dose not constitute a study.

I would also suggest you refrain from using any studies quoting incapacitation times of goats to possible similarities in people. Goats are a horrible comparison to people. Goats have a notoriously low will to live, that is why the U.S. Military uses them in advanced medic courses as training aids.

Kachok
September 23, 2011, 09:58 AM
OK let me sum up the "hydrostatic shock" theory. Yes bullets to create a shock/temporary wound cavity, yes it does inflict some level of additional damage, no it does NOT outweigh the need for penatration and crushed tissue through the vital organs of the target....not even close. NEVER EVER choose a hangun bullet for the size of it's pressure wave or shock cavity, the FBIs Handgun Wounding Factors and Effectivness handbook discribes it best. Basicly they say that reliable stopping is a result of rapid blood loss not a shockwave. According to the FBI all handgun rounds should penatrate to a MINIMUM of 12" to be effective, so forget all the hype around fragmented ammo it is just that hype nothing more. Think about it, what causes more phisical damage, an 22LR bullet passing through the heart and lungs or a 45 ACP stretching the fat and muscle tissue for the first 5"? If you have to think about that you don't know much about terminal ballistics. Energy dump theory belongs in the dump, relying on a pressure wave to casue a concussion like effect to stop a threat is simply not even close to reliable. Plowing a 3/4 inch permanate wound cavity through the vital organs is not perfect nor usualy instant, but it is the most reliable thing we can achieve at handgun speed/energy levels. A determined attacker can function for 15 seconds with complete loss of blood pressure to the brain, this is the result of residual oxygen in the brain, so if you are expecting a bang flop out of any handgun bullet you will be sorely dissapointed.

Loosedhorse
September 23, 2011, 10:58 AM
Many individuals who have not had technical training have nonetheless heard of Newton’s laws of motion, but most of them aren’t really familiar with these laws and would be surprised to learn Newton’s laws describe forces and momentum transfer, not energy relationships. The dynamic variable that is conserved in collisions is momentum; kinetic energy is not only not conserved in real collisions, but is transferred into thermal energy in a way that usually cannot be practically modeled.I'm not sure what MacPherson's point here is.

The fact that Newton's Laws of Motion don't mention energy does not change the fact that Conservation of Energy is a law of physics. Energy is conserved in collisions: if a bullet hits an object and does not emerge, then all off the bullet's energy has been absorbed by (or dissipated by, or "dumped into") that object. Some of that energy is used for destroying tissue, some for creating (temporary) movement of tissue (and that movement is eventually changed to heat as the tissue again comes to rest), and some to shock wave (which also eventually becomes heat).

Fine. How does that argue for or against BPW? Why does it matter if Newton mentioned energy or not? He seems to be condescending ("... most of them aren’t really familiar..."), but for no cause, and to no purpose.Basicly they say that reliable stopping is a result of rapid blood loss...Yes, or loss of CNS function. In other words, rapidly lethal wounds. And yet we know that the majority of those suffering handgun wounds survive.

WISQARS (http://www.cdc.gov/injury/wisqars/index.html) lists 326 law-enforcement-caused firearm deaths and 1663 non-fatal law-enforcement firearm injurys for 2008. The implication is that something other than lethal injury stops the majority of attackers. The FBI says we should ignore that; and from a "what you can plan for and predict" perspective, I see their point. But I'm not sure I ready to, as they do, simply ignore the results of most gunfights.

Kachok
September 23, 2011, 11:26 AM
I don't think the FBI is ignoring the fact that the vast majority of handgun shots are not leathal, they are making a case for what is effective on a detirmened threat, hydrostatic shock does not stop them, temporaory cavity does not stop them, only loss of blood pressure leading to incapacitation or death stops them reliably, aside from a CNS shot anyway. Creating rapid blood loss is best aheived by penatrating blood bearing organs or major vesles/artiers. Expanded bullets increase the chances of crushing, ripping these targets, but having enough penatration to reach these targets is the the most fundimantal aspect to lethality/incapacitation ability. Only a small handful of people have tried to depate me on this topic, and usualy those who have tried don't know enough about termianal ballistics to actualy debate, much less realize when they are just plain wrong. They just spout whatever they read on some highly bias website for whatever handgun caliber they worship.
Bullet construction has alot more to do with terminal performance then weather it is a 9mm, 40, or 45. I have seen standard pressure 9mm out perform poorly designed 45s and I have seen 45s make huge permanate wound cavities that surpass the more powerful .40 S&W.

Loosedhorse
September 23, 2011, 11:44 AM
they are making a case for what is effective on a detirmened threat, hydrostatic shock does not stop them, temporaory cavity does not stop them, only loss of blood pressure leading to incapacitation or death stops them reliably, aside from a CNS shot anyway.So, is the conclusion is that 83% of those shot by LEOs were simply not that determined, or that they were rescued despite lethal injury, or that they received non-fatal injury that nevertheless incapacitated them by blood loss or neurological injury? Because 83% ended up injured, not dead.

BTW your statement "hydrostatic shock doesn't stop them" is exactly what we've been discussing. I think if you added "every time" to that statement, everyone would agree; if you add "ever," now many would disagree.Only a small handful of people have tried to depate me on this topic, and usualy those who have tried don't know enough about termianal ballistics to actualy debate, much less realize when they are just plain wrong. They just spout whatever they read on some highly bias website for whatever handgun caliber they worship.I'm sure you don't include me or the others here in your broad, pre-emptive ad hominem swipe at those who hold a different opinion? :)

Kachok
September 23, 2011, 12:38 PM
I did in fact state that hydrostatic shock was not a reliable method of incapacitation, not that it never happens. Heck I have seen it on several occasions with rifle bullets on game anamals, but of all the handgun shots that I have seen on two legged and four legged targets that were not CNS hits non of them were bang flop kills, with the exception of a 44 magnum killing a traped hog at point blank range. When you are talking THAT kind of power on that size target, I will be very clear in stateing that rapid incapacitation via remote shock to the upper circulatory system causeing brain trama is not just possable but somewhat likley to happen. It is not really an instant kill, but the target bleeds out while unconscious.

2zulu1
September 23, 2011, 02:03 PM
I'm not sure what MacPherson's point here is.

The fact that Newton's Laws of Motion don't mention energy does not change the fact that Conservation of Energy is a law of physics. Energy is conserved in collisions: if a bullet hits an object and does not emerge, then all off the bullet's energy has been absorbed by (or dissipated by, or "dumped into") that object. Some of that energy is used for destroying tissue, some for creating (temporary) movement of tissue (and that movement is eventually changed to heat as the tissue again comes to rest), and some to shock wave (which also eventually becomes heat).

Fine. How does that argue for or against BPW? Why does it matter if Newton mentioned energy or not? He seems to be condescending ("... most of them aren’t really familiar..."), but for no cause, and to no purpose.Yes, or loss of CNS function. In other words, rapidly lethal wounds. And yet we know that the majority of those suffering handgun wounds survive.

WISQARS (http://www.cdc.gov/injury/wisqars/index.html) lists 326 law-enforcement-caused firearm deaths and 1663 non-fatal law-enforcement firearm injurys for 2008. The implication is that something other than lethal injury stops the majority of attackers. The FBI says we should ignore that; and from a "what you can plan for and predict" perspective, I see their point. But I'm not sure I ready to, as they do, simply ignore the results of most gunfights.
I would suggest you read MacPherson's book, Bullet PenetrationModeling the Dynamics and the Incapacitation Resulting from Wound Trauma, second edition 2006 printing.

481 and I did an experiment comparing a higher energy 10mm round vs a lower energy .45auto round. A simple explanation of why the momentum model is better than the energy transfer model;


Momentum vs Sectional Density
By 481


While sectional density is part of the overall terminal performance picture, that parameter is "redefined" at/during expansion. Penetration depth is inversely proportional to the expanded cross-sectional area of the recovered bullet and directly proportional to the velocity of the bullet at the instant of impact. The dimension of the frontal area of the expanded bullet induces drag (effectively behaving as a "brake" as it traverses the media) and when this dimension increases (final expansion diameter) drag increases by the square of the difference in the expanded radius which is effectively ΔA = πΔr2

Therefore, while the effect of the difference between the 10mm's and the .45's final expanded diameter might seem insignificant, it isn't.

The sectional density for each respective round decreases significantly and the one that expands proportionately less than the other gains an advantage in its 'new' and somewhat greater sectional density.

Numerically speaking, the 10mm's sectional density decreases from 0.16071 to 0.05278 (33% of its prior sectional density) and the sectional density of the .45 decreases from 0.16118 to 0.07105 (44% of its prior SD) allowing the .45 load to destroy 6.25% more soft tissue and penetrate 1.33 inches farther/deeper than the 10mm despite the 10mm load's greater KE (+214 fpe/ +53% more than the .45).

This phenomena clearly demonstrates why a "momentum" model is a better means of quantifying hard terminal ballistic performance than an "energy" model.

10mm 180 gr. Remington Golden Sabre JHP
Impact velocity: 1243 fps/618fpe
Average recovered diameter: 0.698"

Vcav = 389.302 fps
Mw = 58.906 grams (2.078 ounces)
Xcm = 33.361 cm (13.134 inches)

.45ACP Winchester Bonded PDX1 230 gr. JHP
Impact velocity: 889 fps (404fpe)
Average recovered diameter: 0.680"

Vcav = 392.366 fps
Mw = 62.603 grams (2.208 ounces)
Xcm = 36.748 cm (14.468 inches)



For obvious reasons, MacPherson does not support the hydrostatic shock theory.

Loosedhorse
September 23, 2011, 02:53 PM
I would suggest you read MacPherson's book, Bullet PenetrationA presumptive, condescending response. I've read it, although my copy is dated 2005. Perhaps you would be so good as to tell us on which page MacPherson explains why conservation of energy doesn't apply to wounding?A simple explanation of why the momentum model is better than the energy transfer modelMomentum has the better correlation to permanent wound channel, yes. And if you have already decided that wound channel is all that matters for incapacitation, then you have your answer. But, your answer depends entirely on the assumption that permanent wound channel is the only method of incapacitation.

So it's a very good answer to the question I didn't ask, and a non-response to the one asked.

I asked: what about those 83% wounded?

Kachok
September 23, 2011, 03:18 PM
Permanate wound cavity is the single most important factor in terminal ballistics (aside from shot placement of course) concerning incapacitation with handgun rounds. Shock incapacitation is simply not reliable, not with 357 mags, not with 10mms and most certainly not with 9s 40s and 45s. I have yet to find any crediable study supporting shallow penatrating fragmented shock bullets as the best method of self defence. Every crediable source I have ever found has said the opposite, shock is great, but unlike high speed rifle bullets handgun rounds simply are not moving fast enough to stretch the soft tissue beyond it's elastic limits. Proper expansion and 12-18" penatration is what you need for effective terminal performance period. Virtualy all quality 9mms 40s and 45 HPs will perform within that range, none make a gallon sized shock cavity like a high speed rifle round, not even close, but they are still effective at stopping attacker that is what they are designed for.

pisc1024
September 23, 2011, 11:19 PM
So, is the conclusion is that 83% of those shot by LEOs were simply not that determined, or that they were rescued despite lethal injury, or that they received non-fatal injury that nevertheless incapacitated them by blood loss or neurological injury? Because 83% ended up injured, not dead.



So what percentage of those people shot by police, or anyone else in that matter, showed signs of brain damage that was not present beforehand? 83% of people were stopped by non life threatening wounds, so show me the numbers that indicate any of them have brain damage.... I have seen a few victims of gsw in my life, and none of them show any signs of TBI...

Shawn Dodson
September 24, 2011, 01:05 AM
Odd Job writes: Thanks for providing that, Michael Courtney (I know you are traveling incognito, but you and I both know that it is well known who "Pasteur" is)

So, who is "Pasteur"?

Is this person Michael Courtney, Amy Courtney, or somebody else promoting/defending the Courtney's hypothesis on their behalf?

I've personally asked "Pasteur" if he/she is indeed one of the Courtneys but this person has refused to be honest and answer with a simple "yes" or "no". The usual response is an attempt to deflect the question.

Michael Courtney is known to run around various firearms related discussion boards (as well as Wikipedia) to post, promote, quote, and defend his pet theory - Ballistic Pressure Wave - to gullible laymen. Michael Courtney suddenly stopped posting after the mysterious "Pasteur" appeared a couple of years ago.

The Courtneys' "ballistic pressure wave" papers have been reviewed by Dr. Gary K. Roberts ("DocGKR" at M4carbine.net) and Dr. James S. Williams (see article about Dr. Williams by Massad Ayoob (http://warriorspiritbooks.com/pdf/Tactical_Anatomy_Review.pdf) and Dr. Williams' website (http://www.tacticalanatomy.com/)), and both have independently concluded that the claims made by the Courtneys (Pasteur?) are not supported by the references they cite.

Dr Williams responded directly to "Pasteur": "Your deer-incapacitation study is, methodologically and physiologically flawed beyond description and in the real world, irrelevant. If you find the mathematics interesting, more power to you; but in terms of applicability to living physiological systems of any species, no conclusions can be drawn from your method and results."

Dr. Williams also wrote: "I have been far too busy to do a detailed critique of the inferences and conclusions you have published based on the work of Gorannson and Suneson, but I have read your papers as well as having reviewed both Gorannson and Suneson's work. Not only have I reviewed them myself, but I have also reviewed them with other persons with extensive background in physiological research, both in vivo and in vitro.

Neither I nor anyone I have reviewed these papers with is particularly impressed with the applicability of these studies to the physiology of human GSW's. The papers published by Wong's group which you also rely on do NOT support the assertions you have ascribed to them, and upon which you based the hypothesis upon which you based your research questions."

Odd Job
September 24, 2011, 06:40 AM
For whatever reason, he doesn't want to post under his real name and he can neither confirm nor deny that he is posting under the name Pasteur. Probably not worth going into that: if he has two accounts on THR I'm sure the mods would sort it out, perhaps he even notified them before switching from Courtney to Pasteur for commercial reasons.
The main thing to note is that he is here in this thread, it's worthwhile acknowledging that and keeping it civil (and of course, knowing who it is who is supporting the hypothesis. We wouldn't want to accuse Pasteur of being a sock puppet)
Anyway, back to the discussion...

do NOT support the assertions you have ascribed to them

Dr Williams used a very good word there, the word is "ascribed" and it means attributed to. It is a recurring pattern in Dr Courtney's "works." He conducts or reports on an experiment and then attributes the results to the ballistic pressure wave.

My favourite example of this is the raccoons in buckets experiment:

http://www.ballisticstestinggroup.org/lotor.pdf

He ascribes the incapacitation of these raccoons to a ballistic pressure wave and notes that there was one case (in the rifle group) where a raccoon died immediately and several cases where raccoons died within 24 hours.
What I would liked to have seen, BEFORE ascribing these deaths to coupling of a ballistic pressure wave to the raccoons' bodies, is cause of death or at LEAST the exclusion of drowning or focal head injury as the mechanism. It isn't unreasonable to ask this, because if you have a raccoon trapped in a bucket and you rapidly displace water by means of gunshot, it isn't a far stretch of the imagination to wonder whether these raccoons aspirated the water from the bucket. It is also not unreasonable to enquire whether these raccoons hurt themselves on the rigid milk crate when the shots were fired and they tried to get away. He doesn't document whether they thrashed around in the buckets during the 3 seconds they were trapped there. There is a lot of stuff he doesn't document, and you have to ask why.
It is an interesting ethical paradox also: Dr Courtney previously refused to do the deer testing he has recently referenced (albeit without control subjects and with rifle injuries) on the grounds that the deer may sustain head injuries when falling which could confound any documented findings of intracerebral damage. The sprinkles on this delicious pie was his apparent reluctance to bait the deer over a soft landing for fear of resprisals by PETA.

Shooting deer over a soft landing = bad, but shooting raccoons in buckets and observing them die up to 24 hours later = okay.

:confused:

You have to ask yourself why he didn't have those animals analysed by certified veterinarians. The same applies to the original deer experiments: what assurance do we have that the rapidly "incapacitated" deer were not subject to a musculo-skeletal incapacitation?

He ascribes the results of the deer shooting to the ballistic pressure wave.
He ascribes the results of the raccoon shooting to the ballistic pressure wave.

The best thing he has done in the last 5 or 6 years on this mission, is the last set of deer tests where he has documented physical evidence of haemorhages in three deer shot with rifles.
The integrity and value of that experiment is subject (in my opinion) to the dependencies I mentioned in a previous post. We have yet to see those.

However, I stand by what I said, which is (with the provisos mentioned) that the last experiment cannot be dismissed out of hand. It's a small sample with no controls and no handgun injuries, but nonethless it is the right direction to be heading in my opinion. With that last valuable evidence in hand, I have to wonder why he insists on referencing Strasbourg Goat tests and Marshall and Sanow data. If you have a PhD and you are on a mission to get a hypothesis moved into the arena of a generally accepted theory, surely it is best to stick with clean data from legitimate experiments?

Pity it took all this time to do it, he might have had less resistance if he had set out to do the experiements in a forthright manner without the abovementioned chicanery from the start. Dare I say it, he might have saved some money also.

Loosedhorse
September 24, 2011, 03:58 PM
So what percentage of those people shot by police, or anyone else in that matter, showed signs of brain damageFirst, I do not conclude that those incapacitated by BPW (presuming that happens) would show any overt "sign" of brain damage (depending on what you mean by sign; loss of consciousness is a sign); they might have pathological findings on autoptsy, but few survivors volunteer for that!

Again, concussion victims typically show no brain changes on standard neuro-imaging; that does not change the fact that they suffered concussion. So, if a BPW-incapacitated person showed no neuro-imaging changes, that fact would be similarly not exclude a BPW.

And lastly, I didn't claim that 83% of the shot were stopped by BPW; I claimed they were not stopped by rapidly fatal injury. Therefore, saying that inflicting massive hemorrhage or significant CNS damage (wounds that would be rapidly fatal) is the way attackers are incapacitated is proposing a theory that seems to miss 83% of the actual incidents.

Some of us are still interested in that 83%, even if we are told that only the 17% were incapactiated "the right way."

Kachok
September 24, 2011, 05:21 PM
Too many variables in that 83% figure. The mindframe of the shootie, drug use, number of cops in the situation, shot placement, proper bullet expansion, health of the shootie prior to being shot........etc. I only like to deal in tangiable facts that can be tested over and over again. Everything else is so subjective since nobody not even the FBI keeps a detailed statistics log of every shooting, attempts have been made to compile such lists but have been so heavly tainted by bias that they have all been worthless. Common sence has to come into play somewhere to cut throuh the BS. The larger the wound canal and deeper the penatration the more blood bearing organs can be damaged and the faster the loss of bloodpressure. The 124gr 9mm Gold Saber makes an impressive 5.1 cu in wound canal, the 155gr .40cal Gold Dot makes a slightly larger 5.9 cu in wound tract, and the 230gr Gold Saber 45 ACP make a monster 6.3 ci in wound all penatrate to the 14" range, all make a 25 cu inch+ temporary cavity if you put stock in that stuff. I would not hesetate to use any one of those in an emergengy situation.

Loosedhorse
September 24, 2011, 06:46 PM
Okay. So, "too many variables" and "too subjective" means we should ignore the 83%, and concentrate on the 17%. Because only the 17% is free of BS?

No alternative?

Kachok
September 24, 2011, 07:31 PM
No don't ignore any facts, God only know it is hard to find them through the piles of BS, just take them with a grain of salt since there are so many variables involved. I just don't buy that shock took down those 83% that did not die. No 45 357 or 10mm is a 100% one shot stopper that is no secret. Most of the time once someone is shot it makes them much more complient, you usualy don't have to keep shooting, I have seen more then my fair share of shootouts (none in person thank God), I spent two years in LE in Texas.

pisc1024
September 25, 2011, 12:45 AM
First, I do not conclude that those incapacitated by BPW (presuming that happens) would show any overt "sign" of brain damage (depending on what you mean by sign; loss of consciousness is a sign); they might have pathological findings on autoptsy, but few survivors volunteer for that!.

I would think that if a person was shot and stopped solely by the damage caused to the brain he or she would exhibit permanent signs of brain damage. This would by similar to the signs of TBI exhibited by military personnel who were the victims of an IED strike. These military personnel display these signs immediately after the strike, and will continue to show signs of TBI long after if not permanently. Why then has there never been a study or even a question of people who were victims of GSW possibly exhibiting signs of TBI too?

Again, concussion victims typically show no brain changes on standard neuro-imaging; that does not change the fact that they suffered concussion. So, if a BPW-incapacitated person showed no neuro-imaging changes, that fact would be similarly not exclude a BPW.

What is being clamed by Dr Courtney is damage to the brain that is more than just a concussion. So while you may or may not be able to see a concussion (I honestly don't know), you should be able to see the damage spoken of by Courtney.

And lastly, I didn't claim that 83% of the shot were stopped by BPW; I claimed they were not stopped by rapidly fatal injury. Therefore, saying that inflicting massive hemorrhage or significant CNS damage (wounds that would be rapidly fatal) is the way attackers are incapacitated is proposing a theory that seems to miss 83% of the actual incidents.

Some of us are still interested in that 83%, even if we are told that only the 17% were incapactiated "the right way."

There are other factors that are involved with how a person reacts to being shot. These factors are the "intangibles". You can't assign a number on a chart to them. They can't be taken into account as a known factor. That being said, you should never count on them being in your favor. The guy who is attempting to assault you may piss his pants at the mere sight of a fire arm in your possession, or he may be a combat vet who is not fazed by being shot at. You just don't and can't know until after the event has played out. That being said, I feel that Courtney and others are trying to come up with an explanation for the inexplicable. I think that people are reaching for straws. This is fine and dandy, but in the real world it is a dangerous train of thought. People are trying to account for something that they simply cannot quantify. This may lead them toward round X which has a higher velocity, but less penetration. Some may think that if 1100 FPS is good, then 1300 should be better. This is simply not true.
I guess at the end of the day, load what you will in your blaster, and I'll do the same. I however will depend on proven designs, and things that can be tested for in a real lab setting. This works for the FBI, and many other LE agencies in America, and has worked for me in the past. That is good enough for me.

shadow9
September 25, 2011, 02:28 AM
...IMHO, this thread ended with the post "it's applicable with High-velocity rifle cases, and inapplicable with pistol cases", or something to that note (too lazy to go back and re-quote exactly)

While we can study and bounce %'s back and forth and get scientific about the details, in real-life, you gotta take it ALL in one big ball, because that's how life works. There is the general statistic, then there's the anomalies; the people that have been able to put two .32ACP rounds into both ventricles, or the person that got 7 .45ACP's to the torso, and minus a lot of holes and 3 weeks of painful healing, had no major damage. SHOT PLACEMENT. PERIOD. That's as much as you EVER need to calculate in your ballistics decisions and carry decisions.

As far as HydroStatic shock...well, when we were training in the morgue for embalming school, a "trade-trick" is to apply SLIGHT pressure to the sternum/chest, which COMPRESSES the internal organs enough to actually INFLATE the jugular vein - which we need to utilize to facilitate drainage during the embalming process. Mind you, this thing is as thin as tissue-paper, stretches like a rubber band, but a sharp finger-nail will snap it in half before you can say "oh, ****".

THAT said, think for a second folks. We all know that the FASTER something hits something else, the more kinetic energy is imparted. Car-crashes. Motorcycle-crashes. A 22LR vs a .223 hitting a watermelon (which makes the watermelon pop?). This causes a Temp Wound cavity (which will vary on bullet tilt or shape), which we're ALL familiar with in ballistics tests. Also, mind you, the human body is comprised of 70% water, ideally. Trust me, it looks ALOT different without that 70%.

Now, if you're STRETCHING the tissues OUTWARD away from the bullet, but they're not BREAKING (see Permanent wound cavity), and that STRETCH is confined to an area (the rib-cage/peritoneum), then in order to make SPACE for that stretch, you are COMPRESSING those tissues TOGETHER, CardioVascular system INCLUDED. The aortic arch, the subclavian, the brachiocephalic, the ventricles and atriums, the arterioles and the alevolae are ALL affected with a high-speed centre-mass shot.

Now, if my hand applying SLIGHT pressure could actually INFLATE the jugular enough to PUSH surrounding tissues aside so I could see it, in an UNPRESSURIZED CV system, imagine what an ALREADY PRESSURIZED system would do if you took the internal organs, especially those in the thoracic cavity, and COMPRESSED them together at VERY high speed(and I'm talking compression in amounts of shoving them into spaces 75-85% of their normal "real estate" allowed), then that's going to INSTANTLY deflate the surrounding CV system.

Since our CV system is all hooked together, it's gonna shove that blood above the impact, UP, and the blood below the impact, DOWN. Well, in an upper-thoracic hit (which is close to the head, and the farther up we go, the smaller the pipes get) there's ALOT of pressure through the CV system upwards, and it all meets up in the circle of willis in the brain. That's alot of blood, at once, in a tiny space, meant for minimal pressure, and with weak-piping. ENTIRELY plausible for a bullet impact to cause a remote cerebral hemorrhage with that sort of pressure, provided the bullet is:


A) Big enough (.375 H&H, .416 Rigby, .458 Lott, etc. etc.), or-
B) Moving VERY quickly.


Simply put:
Ever seen the disruption of a 5.56 passing through 12x12x16 of Ballistic Gel? It doesn't leave a huge hole behind, but for a few seconds, the block gets about 220% larger while the bullet is going through.
Make your water-filled thoracic cavity, namely it's organs, 190% larger, instantly, and tell me where THAT blood's gonna go...


Just my uneducated opinion in laymans terms on the matter. :) Dissect and disparage as you may.

Cheers!


P.S. - final note: The HydroStatic shock theory I doubt would work on a femoral-shot or a tibial-impact, or even one to the axillary or brachial regions. There just isn't enough physical tissue to compress there to cause remote damage, or in the case of the femoral, you're fighting the whole CV system from the artery to the neckline, and you're fighting gravity. Short story, you'll take the leg off or blow the thigh apart/break the femur much before you pressure-spike the CNS.

Loosedhorse
September 25, 2011, 09:24 AM
just take them with a grain of saltAgreed.I would think that if a person was shot and stopped solely by the damage caused to the brain he or she would exhibit permanent signs of brain damage.Again, it depends on what is meant by "signs". But while signs of "functional deficit"--almost always temporary--are defining of concussion, physical evidence of brain trauma is not. Go figure. It is that feature that for years caused concussion to be underestimated, especially in contact sports.What is being clamed by Dr Courtney is damage to the brain that is more than just a concussion.No. The fact that vascular damage in the CNS has been seen in some cases of remote bullet injury gives plausibility to the idea that force is trasmitted to the CNS. It does not then follow that tissue damage is required to cause change of consciousness. Petechial hemorrhage (for example) is variably visible on MRI, depending on extent--and again is typically not seen in simple concussion.I feel that Courtney and others are trying to come up with an explanation for the inexplicable.I think any scientist would take that as high praise. However, perhaps you meant "assigning a false explanation."

We should remember the fable of the guy searching for his keys at night under a lamp-post. Passerby tries to help: "So where'd you drop them?" "Over there, about 20 yards away." "So...why are you looking here?" "Because this is where the light is."

The researchers who choose to ignore the 83% of shootings do so because they don't have a model to explain them, so they confine themselves to the light of their particular lamp-post. The Courtneys have decided to wander away from that lamp-post...and may in time build another. But the scientific effort realizes that the really interesting answers are out there in the dark, and someone needs to look for them, even while others claim it's just too dark.

2zulu1
September 25, 2011, 02:54 PM
Now, if you're STRETCHING the tissues OUTWARD away from the bullet, but they're not BREAKING (see Permanent wound cavity), and that STRETCH is confined to an area (the rib-cage/peritoneum), then in order to make SPACE for that stretch, you are COMPRESSING those tissues TOGETHER, CardioVascular system INCLUDED. The aortic arch, the subclavian, the brachiocephalic, the ventricles and atriums, the arterioles and the alevolae are ALL affected with a high-speed centre-mass shot.

Now, if my hand applying SLIGHT pressure could actually INFLATE the jugular enough to PUSH surrounding tissues aside so I could see it, in an UNPRESSURIZED CV system, imagine what an ALREADY PRESSURIZED system would do if you took the internal organs, especially those in the thoracic cavity, and COMPRESSED them together at VERY high speed(and I'm talking compression in amounts of shoving them into spaces 75-85% of their normal "real estate" allowed), then that's going to INSTANTLY deflate the surrounding CV system.




The high speed compression you speak of has a time window of <1 millisecond during a gun shot wound.

The stretch cavity (temporary wound channel) will actually collapse and reform repeatedly with a diminishing amplitude until it settles down to what will be the permanent cavity during a time window of one to five milliseconds.

In service calibers, wound trauma incapacitation is caused by cell comminution and laceration.

Kachok
September 25, 2011, 03:48 PM
All reputable souces I have read treat fragmintation and temporary cavity as lesser secondary effects, while there are something their importance pales in contrast to the bullets primary function to crush and lacerate soft tissue. Now I do not have any hard scientific studies to back up this next statment so please take it with a few grains of salt, but from what I have seen over my years of hunting is that higher speed shock inducing projectiles seem to create a greater sensation of pain then low speed projectiles. Before you laugh at me take it to the extream for contrast. An arrow moving at only a couple hunderd fps can cause just as much rapid blood loss as most rifle bullets moving 10 times as fast, and both can reliably kill within seconds, but the deer shot with an arrow will almost always run off like nothing touched him at first. A deer shot with a 100gr 243 SP (very high perssure wave) will often casue them buckle a little on the side where they were shot, many times they will turn eraticly after being hit, Now I don't speak the deer language but I am just guessing he felt that more then an arrow. I would have to try it a few times with a large caliber slow moving bullet before I can say that with a great sence of certenty since arrows are very different then bullets in several ways, but it does seem logical. OK you can laugh now.

Loosedhorse
September 25, 2011, 03:59 PM
All reputable souces I have read treat fragmintation and temporary cavity as lesser secondary effects...Well, you and I may have different definitions of "reputable," but perhaps we agree on Martin Fackler, and he says this (http://rkba.org/research/fackler/wrong.html):In the Vietnam era, the major role played by bullet fragmentation in tissue disruption was not recognized (8). It is now appreciated (12-14) and documented (Fig 3) that bullet fragmentation is the predominant reason underlying the M-16's increased tissue disruption.

... A similar temporary cavity such as that produced by the M-16 (Fig 2), stretching tissue that has been riddled by bullet fragments, causes a much larger permanent cavity by detaching tissue segments between the fragment paths. Thus projectile fragmentation can turn the energy used in temporary cavitation into a truly destructive force because it is focused on areas weakened by fragment paths rather than being absorbed evenly by the tissue mass. The synergy between projectile fragmentation and cavitation can greatly increase the damage done by a given amount of kinetic energy.
There are, by the way, handgun rounds that produce both fragmentation and large temporary cavities. The Remington .357 125gr SJHP is perhaps the most famous, but there are others.

brickeyee
September 25, 2011, 04:43 PM
The high speed compression you speak of has a time window of ~ 1 microsecond during a gun shot wound.

Millisecnds maybe (0.001 seconds) but not microseconds (1e-6, 0.000001 seconds).

bullets are not moving that fast.

Even at 3,000 ft/sec a bullet only moves 0.003 feet (0.036 inches) in a microsecond.

In 1 millisecond it moves 36 inches.

Kachok
September 25, 2011, 08:28 PM
Well, you and I may have different definitions of "reputable," but perhaps we agree on Martin Fackler, and he says this (http://rkba.org/research/fackler/wrong.html):
There are, by the way, handgun rounds that produce both fragmentation and large temporary cavities. The Remington .357 125gr SJHP is perhaps the most famous, but there are others.
The 5.56 is a whole different story, I was talking in the context of handgun rounds, the 5.56 is moving fast enough to throw fragmentation outside the regular wound cavity causing a noticable secondary wounding effect. As well as a truly useable amount of shock. No handgun round not even the 357 mag can throw it's fragmentation outward a couple inches or more, it pretty much drags along inside the permanate wound canal. At handgun energy levels fragmentation is not a good thing anwyay, the deformation takes up excessive amounts of the bullets energy, and since it reduces the mass it automaticly reduces penatration. I have seen several 357 mag tests and none showed useful deep fragmentation outside of the wound canal.

Loosedhorse
September 25, 2011, 09:14 PM
I was talking in the context of handgun roundsAh, well, a late clarification is better than none, I guess. Some would consider this an attempt to rescue your false statement: "Er, uh, what I meant was...":uhoh:it pretty much drags along inside the permanate wound canalOdd statement. Wherever a fragment goes, it defines an new, separate wound canal...so, yes, it travels with the permanent channel--the very one it creates.

Some examples:

https://www.usconcealedcarry.com/wp-content/uploads/2011/05/hit-them-hard-fragmented-remains.jpg

http://www.shootingillustrated.com/wp-content/uploads/2011/08/DoubleTap-10mm-135-gr.-Nosler-JHP-354x200.jpg

Caption for this lower image: "By driving Nosler’s 135-grain JHP bullet at more than 1,500 fps, there is massive fragmentation. The result is a 10 mm load that does frightening things to a gelatin block."

Fackler does not make a requirement that the fragments be thrown "outward a couple inches or more"--that seems to be a requirement you yourself have added. And, those fragments shown above do seem to have traveled more than a couple of inches.

I get this circular reasoning a lot: fragments aren't important for handguns, because handguns only throw fragments so far, and we know that isn't far enough, because fragments aren't important for handgun rounds. :rolleyes::Dnone showed useful deep fragmentation outside of the wound canal. Again, as long as you get to define "useful", then that is obviously true--with useful defined as "whatever is beyond what handguns can do." You have given no evidence why handgun-style fragmentation would not be useful in producing, as Fackler puts it, "synergy between projectile fragmentation and cavitation."

Kachok
September 25, 2011, 10:38 PM
You know good and damn well that I was talking in context of handgun bullets so quit trying to skew every word I say! I have made no such insulting attempt on you. Just to claify for everyone I am speaking in the context of deep penatrating expanding bullets, not FMJs and not rounds designed to completly break apart on impact (like quickshocks). I am talking about hydrostatic shock in bullets that meet the requirements of LE use unless otherwise clearly stated. Those BG tests are still not showing me adaquate panatration with effective use of fragmentation, or a permanate wound cavity being noticably expanded by the shock wave stretching the tissue beyond it's elastic limits. So try again.

Kachok
September 25, 2011, 11:03 PM
This is that I am talking about, A bullet that drives to 14" even after passing through a bone plate, and leaves a nasty trail of fragments thrown outward of the permanate wound canal, creating hundreds of secondary wounds. This is NOT a handgun bullet, this is a 168gr Burger VLD, If a handgun bullet could create a similar effect I would shoot nothing else.

2zulu1
September 26, 2011, 02:17 AM
Caption for this lower image: "By driving Nosler’s 135-grain JHP bullet at more than 1,500 fps, there is massive fragmentation. The result is a 10 mm load that does frightening things to a gelatin block."

Fackler does not make a requirement that the fragments be thrown "outward a couple inches or more"--that seems to be a requirement you yourself have added. And, those fragments shown above do seem to have traveled more than a couple of inches.

I get this circular reasoning a lot: fragments aren't important for handguns, because handguns only throw fragments so far, and we know that isn't far enough, because fragments aren't important for handgun rounds.


It appears the illustration of the fragmenting 135gr Nosler @1500fps penetrated less than 7" of gel. The illustration you posted does not meet Courtney's 12" penetration recommendation.

In Courtney's own words;


Recommendations

The FBI recommends that loads intended for self-defense and law enforcement applications meet a minimum penetration requirement of 12” in ballistic gelatin.[8] Maximizing ballistic pressure wave effects requires transferring maximum energy in a penetration distance that meets this requirement. In addition, bullets that fragment and meet minimum penetration requirements generate higher pressure waves than bullets which do not fragment. Understanding the potential benefits of remote ballistic pressure wave effects leads us to favor loads with at least 500 ft-lbs of energy.



In response to your quote outlined in red above; in MacPherson's WTI book, that you claimed to have read, MacPherson clearly states why handgun bullet fragmentation is a bad thing for wound penetration.

As far as the 5.56 55gr FMJ bullet that was commonly used in Vietnam, the bullet was/is designed to fragment at the cannelure. I observed a VC who had an entrance hole above his left nipple and an exit wound out his left buttocks.

Loosedhorse
September 26, 2011, 07:46 AM
You know good and ... well that I was talking...No. I have assumed you are articulate--remember, you claimed to be quite the debater--and mean what you say. As you insist, I remove the assumption that you are able to express yourself competently.This is that I am talking aboutDoesn't matter what you're talking about; what matters is your proof of your claim that the fragmentation of handgun bullets cannot produce the Fackler-stated synergy between fragments and temporary cavitation.that you claimed to have read, MacPherson clearly states why handgun bullet fragmentation is a bad thing for wound penetration.Which I claim to have read, and have read, despite your bald accusation of dishonesty. (More ad hominem--can you really not sustain your argument without it?).

Duh. Of course fragmentation decreases penetration, and of course MacPherson, having decided that penetration is all that matters, would note that.

However, to bring you up to date, we were discussing the "synergy between projectile fragmentation and cavitation" that Fackler mentions. Perhaps you were too busy thinking up witty insults to keep up? Feel free, by the way, to insult Fackler for not mentioning penetration in this "synergy" he supposes.The illustration you posted does not meet Courtney's 12" penetration recommendation.
Courtney does not have a 12-inch minimum, despite your claim. Instead, he says:Selection criteria should first determine the required penetration depth for the given risk assessment and application, and only use pressure wave magnitude as a selection criterion for loads meeting minimum penetration requirements.So, do your risk assessment.

And the gel results--as I think you realize, but try to obscure--where offered simply to refute the tired, circular claim that "handgun bullets don't fragment enough to matter, because they're handgun bullets." If you are now agreeing that handgun bullets can actually fragment enough to be significant, we can shift the discussion on to penetration.

Remember: you are claiming that we MUST concentrate on penetration because temporary cavitation and fragmentation ARE NOT wounding mechanisms. But Fackler says they are, together, in which case there is synergy. When shown a handgun round that seems to utilizes those as valid wounding mechanisms, the shout goes out: "But only penetration matters!"

No. Fackler is talking about fragmentation and cavitation being actual wounding mechanisms, not producing BPW-incapacitation. If you are trying to utilize BPW, everyone claims that is undependable, so you should have a "back-up plan" like penetration (as noted by Courtney). If you are using fragmentation and cavitation as actual wounding mechanisms, you don't need an additional wounding mechanism--though some will still want penetration for additional reasons.

Pasteur
September 26, 2011, 09:26 AM
Papers documenting remote CNS wounding are relevant, because outdated (yet common references in these discussions) works such as HWFE, Bullet Penetration, and IWBA publications assert that temporary cavitation and tissue directly crushed tissue are the sole bullet wounding mechanisms. Remote wounding effects are necessary (but not sufficient) to support physiological incapacitation via “hydrostatic shock.” The data providing evidence for remote wounding effects contradicts supposedly “expert” opinions claiming that remote wounding does not exist. Science is based on supporting claims with published data rather than expert opinion. A long list of scientists and medical professionals have published data supporting remote wounding effects. In contrast, none of the (smaller) group making contrary claims have published work showing the lack of remote CNS wounding using detection techniques that would be sufficiently sensitive to see it in cases where it is expected from the shot placement and energy transfer.

Scientific discussion of incapacitation via of BPW is in terms of probability and averages rather than being an absolute predictor of outcomes in every case. This is consistent with standard practice in assessing the risk of injury and disease in the medical world. Thus the theory that “other factors being equal, bullets with higher ballistic pressure waves incapacitate more quickly, on average” or that “other factors being equal, a bullet creating a higher ballistic pressure wave is more likely to cause incapacitation in under five seconds” is analogous to the idea that “the probability of a broken bone increases with the height of the fall” or “the risk of a blast-induced traumatic brain injury increases with the blast wave pressure.” In contrast to the data-driven studies supporting the theory of more rapid incapacitation (on average), there is no published data contradicting the BPW theory as it predicts more rapid incapacitation. Rather than rehash the same tired opinions for the same handful of “experts”why not show some actual published data that might be capable of contradicting the theory either as applied to remote wounding effects or more rapid incapacitation?

Interested parties would do well to read the 2011 Neurosurgery paper and its citations as well as the 2007 Brain Injury paper and its citations. These papers appear in peer reviewed journals and if the citations did not support the claims they would be easy targets for peer-reviewed published replies in the same journals. However, if those posting criticism in internet forums attempted the same criticism in the peer-reviewed journals, I suspect the original authors, editors, and peer-reviewers would embarrass them with the reasoning and evidence presented in reply. Dialog in scientific journals is more limited to actual data and logic without the propensity to veer off into expert opinions and ad hominem attacks. What does it suggest when support for a theory can cite data from numerous scientific journals and opposition can only cite expert opinions from internet forums and a handful of outdated scholarly sources that also contain more opinion than relevant data?

The behind armor blunt trauma causing remote cerebral effects (depressed EEG, including flatlining and rapid death in some cases in human-sized pigs) occurs with pistol levels of energy transfer to the chest at 233, 386, 569, and 634 ft-lbs. As the energy applied to the chest is increased, the severity of EEG suppression and probability of death is increased. In the case of dogs shot in the thigh experiencing remote brain injuries, the energy transfer levels were 97 ft-lbs in the case of mild remote TBI and 546 ft-lbs for a more serious TBI. In the case of pigs shot in the thigh, 466 ft-lbs of energy and 570 ft-lbs of energy both produced transmission of significant pressure pulses to the brain and resulting damage. The study showing 33 cases of cerebrovascular damage (in 33 cases examined) in humans shot in the chest were with handguns with less than 500 ft-lbs of energy.

No one has claimed that hydrostatic shock/BPW is a reliable incapacitation mechanism at service handgun levels. However, nor is blood loss a reliable mechanism in the time span of most gun fights (less than 5 seconds). If the mechanism reduces the average time until incapacitation, then it is somewhat of a straw man fallacy to claim its absence in all cases except for truly instant incapacitation. Likewise, it is a fallacy to claim that absence of evidence of TBI in cases where sensitive detection techniques were not employed. Finally, when selecting ammunition, does it really matter whether the mechanism by which the BPW produces more rapid incapacitation is a remote CNS effect or a muculo-skeletal effect or a combination of both? Isn't knowing that increased BPW increases the probability of a positive outcome sufficient even if the mechanistic details are still under investigation?

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