The hydrostatic shock theory?

[Pyro]

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).

 

[KodiakBeer]

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]

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]

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]

hydrostatic and shock are dichotomous
a shockwave can not be static

 

[Pyro]

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]

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.

 

[aggieoutlaw]

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.

 

[Slamfire]

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!!

 

[BADUNAME37]

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]

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!!

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.

 

[Derek Zeanah]

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]

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]

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:


That said, for some reason, the 600 grain barnes .510 caliber solid at 2150 fps
well, look at the way the jug disappears:

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:

 

[KodiakBeer]

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.

 

[BADUNAME37]

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]

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:



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

 

[mrmeangenes]

"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]

"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]

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]

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]

Energy dumped in a palm?

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]

Proper Shot placement makes all these arguments moot anyway.

 

[Loosedhorse]

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]

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.