Hydrostatic Shock


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svtruth
November 15, 2010, 11:36 AM
How big a factor do you think it is?
I have heard that in VT they hunt pike with firearms, shooting down into the water over the pike coming into the shallows and recovering the stunned/dead fish, so there it must be a factor.
However, any shot into the chest cavity will be into largely air lungs, probably not a good medium for transmitting shock waves.
I am not a hunter, or a physicist, just curious.
Yes I did do a search before posting.
Thanks in advance.

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papa_bear
November 15, 2010, 12:08 PM
I recently read a report from some students out of MIT. They did some handgun ballistics testing on live deer in a semi controlled environment. They found hydrostatic shock to be a factor on living tissue. Specifically with the 357.sig and the 135gr .40. I cant remember where the report was. I will do some digging later to see if I can find it.

JR47
November 15, 2010, 12:13 PM
With the advent of better instrumentation, hydrostatic shock effects are being found at velocities below 2000 fps, the old floor.

It's witnessed in the temporary cavity created by bullets. It's effect, though, is only now being investigated.

X-Rap
November 15, 2010, 12:26 PM
Concussion/shock in water is a long known effect regarding fish.
Water has a density obviously less than a solid but ask anybody who has hit the water hard while skiing and they will attest that it is not soft.
Bodies being made up of mostly water it stands to reason that hydrostatic shock has increased intensity or effect compared to a dry media when hit with high velocity projectiles.
I'm sure there are parts of a body that are less susceptible to hydrostatic shock but they are also very susceptible to puncture from bullets and fragmentation of bone so it doesn't really matter.
Seeing how a hi power rifle round effects a big game animal makes the concept a little clearer.

Water-Man
November 15, 2010, 12:32 PM
Ever wonder why the .357 MAG 125gr. HP is so effective?

fastbolt
November 15, 2010, 01:28 PM
More of a factor than some folks might like to think ... less of a factor than other folks might like to think.

Unpredictable.

Some folks seem to have an affinity for it almost to the point of it being a "Talisman Effect".

I used to really pay attention to the folks espousing it when I was younger and carried .357 Magnum and .44 Magnum revolvers. Bullet placement and design replaced that in my case.

No longer high on my list of potential performance factors when selecting and using defensive handgun ammunition.

Just my thoughts.

Hk Dan
November 15, 2010, 03:10 PM
I've heard that the temporary cavity size is less important than the speed at which the cavity forms. The "Magic number" for temp cavity wounds to become pertinent is rumored to be around 2300 FPS. I ain't a doctor, but I took a class from one who is also an LFI affiliate on this subject. I trust his words, though they are all I have.

Dan

millertyme
November 15, 2010, 03:44 PM
The research suggests it's more important than it is not.

papa_bear
November 15, 2010, 03:58 PM
this is the paper I was talking about. I might have been a little off on the overall idea. Take it for what its worth.

Handgun Wounding Physics (http://arxiv.org/ftp/physics/papers/0702/0702107.pdf)

I believe Hydrostatic shock is addressed on pages 4 to 6.

robertbartsc
November 15, 2010, 04:48 PM
I was taught in a hunting class that was necessary to get a NY hunting license that you should NEVER shoot into water since bullets often skip over the water surface and this could hurt inocent people.

therewolf
November 15, 2010, 05:02 PM
In the armed forces, the 1911A1 -.45 ACP was replaced by guns which fire a smaller caliber bullet, the 9MM.

Troops have been asking, with partial success, to get the larger bore 1911A1- .45 caliber ACP back in service, for the simple fact that the 9MM rounds don't put a determined attacker down every time on the first shot. The 45 caliber 1911A1 has a strong reputation for having a large enough projectile to do this effectively.

It is theorized that hydrostatic shock has a lot to do with the effectiveness of this caliber of weapon. If this is effectively proven, then there will literally be 100 years of military history to document and support these claims.

Shadow 7D
November 15, 2010, 10:53 PM
Well here is the problem, the most effective test are not widely published, and the one that is seminal, wounding dynamics or something close, done by an army? surgeon with goats is, well yeah. Listen, Medical examiners and trauma surgeons will tell you that it's hard to tell the caliber unless you have the bullet (intact and not majorly deformed) With rifles you see much different wounds than with handguns, and it varies with ammo.

So the gist of this is....
there is great pics of "shock" and temporaries cavities using "homogeneous" tissue simulant, only problem is that the human body is not consistent like gel and is MUCH more complicated.

Hence, when it comes to 'ballistics' I will leave it to the medical and physics experts, ballistics 'experts' bicker;
and choose a round I like, topped with a bullet effectively designed to place maximum energy into the target, and carefully place my shots

BTW, winging someone with a .50BMG, does NOT POP THEM LIKE A WATER BALLOON...
so how does that shock work again?

millertyme
November 15, 2010, 11:08 PM
Well, in the case of the 50BMG, the loss of said wing would put you into shock, not necessarily hydrostatic shock, but the loss of limb kind of shock and the ensuing bleeding to death that comes with it.

It's not supposed to pop you like a balloon. If you were composed entirely of a fluid encased in your skin and supported by your bones, then you would most certainly pop like a balloon. If I read the reports correctly, the hydraulic action of the bullet hitting a fluid in the body, particularly the blood in a major or significant vein, would cause hemorrhaging in the brain and acute damage to the nervous system.

This is what I've read. If all else fails, double-tap.

X-Rap
November 15, 2010, 11:19 PM
High velocity such as that of a high powered rifle cartridge will no doubt have some interesting effects on the body. I have no doubt that the concussion near a major vein or artery could cause a rupture or have a nasty result at the end of its trail be it heart, brain, lung, liver.
Like I said, take a look at big game and how it is affected by HV ammo. I was commenting to some hunting buddies about how a double lung will sometimes let them run an amazing distance spraying blood but other times they will lunge and drop right there.

Kachok
November 15, 2010, 11:37 PM
OK couple quick notes on "hydrostatic shock"
1st of all that is the wrong name for it. Sound travels 5 times faster in water then in air, and not even a 220 swift hits at those speeds.
2nd it is a proven fact that there is a remote wounding effect related to high speed bullets, if you don't beleve that just check out the amount of gunshot meat on a deer after being hit with a 7mm rem mag.
3rd as great as this effect is you cannot depend on it 100% even with somthing as fast as a 44 mag, too many variables in there for "shock" bullets to be reliable.
4th this "shock" is a pressure wave that can be messured in lab tests, and has been by the FBI, I don't have the link anymore but it was a very intresting reading.
5th While shock is great the most reliable man stopers were not always the super light, crazy fast opening bullets, but rather the ones with consistant expansion and aprox 14" of penatration. I don't remember all the top performers but I do remember the 115 gr Carbon was by far the best in 9mm, and the 230 gr Gold Saber was amazing in the .45 ACP.

X-Rap
November 16, 2010, 12:05 AM
Apples and oranges when you compare rifle and handgun rounds.
The anemic 223 shocks circles around the 357 or 44 mag as well as exceeds in penetration.

thezoltar
November 16, 2010, 12:22 AM
anemic 5.56 shock....

http://www.m4carbine.net/showthread.php?t=31666

Full Metal Jacket
November 16, 2010, 12:37 AM
hydrostatic shock only makes a difference in stopping power with high energy loads. it makes little, to no difference with the popular self defense calibers (9/40/45).



The anemic 223 shocks circles around the 357 or 44 mag as well as exceeds in penetration.

standard 223 (non-steel penetrates) tumble when they strike a person, reducing penetration. you'll get more penetration out of the 7.62x39 round, or even the 44 magnum.

see this to see the affects of 223 tumbling/redirection after hitting a feller: http://www.m4carbine.net/showthread.php?t=26905

X-Rap
November 16, 2010, 12:38 AM
The anemic 223 shocks circles around the 357 or 44 mag as well as exceeds in penetration.
__________________
Take a little heathy sarcasim there and also compare that wound to that of a 300 WM.
My point was to define the difference between the common handgun rounds and the lower tier of rifle rounds.
I am not on the boat with those who think the 5.56 is not a worthy caliber.

wacki
November 16, 2010, 12:49 AM
Human autopsy results have demonstrated brain hemorrhaging from fatal hits to the chest, including cases with handgun bullets

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

Full Metal Jacket
November 16, 2010, 12:50 AM
I am not on the boat with those who think the 5.56 is not a worthy caliber.

it's an ok battle round IMO. if it doesn't tumble and just zips through someone without striking a vital organ--the permanent wound cavity is tiny.

i think the 6.8 would be a much better US military round--better penetration, more energy, stable at longer distances, and not much bigger than the 223 so soldiers can hump the same amount of ammo around.

X-Rap
November 16, 2010, 01:02 AM
FMJ I don't doubt that the 6.8 is a fine round but for the cost I think they should wait and decide if they are going to a whole new platform or staying with the old before such a big outlay in funds.
The AR and AK are amazing in their longevity, it seems that the AK platform is going smaller and the AR wants to go up, I guess they will meet somewhere in the middle.

devildave31
November 16, 2010, 01:02 AM
As far as the OP's original question, it depends what you are referring to as "hydrostatic shock".

Are you refering to the reaction of soft tissue to pressure waves created by impact? If so, then I think it does play a decent part based on energy transmitted to the target, which if I understand correctly is greater with a larger size round.

If you are referring to the idea that hydraulic systems in the body, the vascular system for example, can see a sudden spike in pressure that causes more damage to organs/tissue that are not in the immediate vicinity of the wound, then I have my doubts.
I have worked previously on contruction equipment and learned quite a bit about hydraulic systems in general (which your vascualr system is one). In a contained system which has no flexibility, (i.e. steel hydraulic lines) a sudden spike in pressure is likely to do some damage. In a flexible contained system such as a system with rubber hoses, or in the case of the human body, soft tissue veins/arteries, the fluid carriers will be able to flex under a pressure spike. That flex combined with the distance from the wound to a major organ, are going to reduce the noticed spike at a major organ or other catastrophic fail point.

9mmforMe
November 16, 2010, 01:06 AM
"If I read the reports correctly, the hydraulic action of the bullet hitting a fluid in the body, particularly the blood in a major or significant vein, would cause hemorrhaging in the brain and acute damage to the nervous system."

This is what I have read also.

Additionally, there is speculation that resultant pressure increases when impact and contraction of the heart coincide...a massive spike in blood pressure.

Owen Sparks
November 16, 2010, 01:08 AM
Liquids will not compress. Hydrolic jacks work on this principle. Anyone who has ever done a belly flop off the high dive knows that the faster you hit water, the harder it gets. (or something like human tissue that is mostly water) I have seen examples of hydrostatic shock caused by bare handed blows to the body. A simple punch to the stomach can rupture organs and do internal damage many inches away from the location of the blow. I once caught a round kick with safety pads to the ribs in a sparring accident that caused injury to my kidney. The shock wave from that kick traveled all the way through my torso and made me very sore on the opposite side of my back. Granted a bullet is not nearly as heavy as a mans leg but then it is going a whole lot faster. I wonder what the shock wave from a right cross would look like in a block of balistic gell.

X-Rap
November 16, 2010, 01:12 AM
devildave I share you interest in things mechanical but wouldn't want either of us to do surgery. I think there are dynamics at work that exceed that of a simple loader hydraulic system.
The first being a system that is closed as in veins and arteries but yet surrounded buy much of the same material that is circulating plus having some very sensitive equipment at the end of the lines.

Full Metal Jacket
November 16, 2010, 01:35 AM
FMJ I don't doubt that the 6.8 is a fine round but for the cost I think they should wait and decide if they are going to a whole new platform or staying with the old before such a big outlay in funds.

of course, cost is always the major factor (and NATO, unfortunately lol). i think lightweight piston guns (there are quite a few lightweight ones available now) would be the best option for our military.

with the piston system, our guys don't have to worry as much about constantly cleaning their rifles to keep them reliable, as they do with the M16 or M4 gas impingement systems.

devildave31
November 16, 2010, 02:41 AM
devildave I share you interest in things mechanical but wouldn't want either of us to do surgery. I think there are dynamics at work that exceed that of a simple loader hydraulic system.
The first being a system that is closed as in veins and arteries but yet surrounded buy much of the same material that is circulating plus having some very sensitive equipment at the end of the lines.
All i'm saying is that given the flexible nature plus the fact that the highest pressure increase will be at the wound site dissipating outward and that immediately afterwards, the wound itself is going to relieve the pressure, that noticed pressure and damage down the line is going to be a lot smaller than most people give credit. In other words I don't think the extra damage caused by the "hydrostatic shock" is going to be the extra damage that incapacitates or kills.

Maybe one day someone will take some deathrow inmates (Rapists/Murderers) and hook them up to all kinds of pressure sensors, and a computer with all kinds of graphing software and then shoot them a few times with various calibers and loads. Until they do and produce some quantifiable results, I will remain skeptical.

Shadow 7D
November 16, 2010, 02:55 AM
Ok, true a liquid compresses less (as in why do they use a special HYDRAULIC FLUID?? and not water) Blood has dissolved gasses etc, secondly look up petechiael hemorrhaging, and brain swelling/micro bleeds are/can be caused by lack of oxygen, which in the end is what we all die of. So seeing that there is bleeding and attributing it to "hydrostatic shock" is not the same. Not saying it doesn't exist, but the research is kinda hard to do...

brboyer
November 16, 2010, 03:12 AM
Ok, true a liquid compresses less (as in why do they use a special HYDRAULIC FLUID?? and not water) Blood has dissolved gasses etc, secondly look up petechiael hemorrhaging, and brain swelling/micro bleeds are/can be caused by lack of oxygen, which in the end is what we all die of. So seeing that there is bleeding and attributing it to "hydrostatic shock" is not the same. Not saying it doesn't exist, but the research is kinda hard to do...

why do they use a special HYDRAULIC FLUID?? and not water
Lubrication properties
Proper Viscosity
Thermal properties
Corrosion inhibition
etc.

svtruth
November 16, 2010, 10:06 AM
deer season, perhaps some of the hunters among us could look for brain hemmorhages in their quarry.
And thanks to all for an interesting discussion.
If the shock requires impact velocities greater than the speed of sound in the medium, aint gonna happen. Speed of sound in water is 4.3 times that in air, whic is 1100 fps. So we are talking in the neighborhood of 5000 fps.

Kleanbore
November 16, 2010, 11:23 AM
In the report cited above, Courtney and Courtney relate their measurements in experiments involving firing saboted handgun bullets from muzzle loading rifles at a few baited deer, and they point out that they could not have done the same thing with handguns due to velocity loss and handgun inaccuracy at deer hunting distances. OK, then.

Courtney and Courtney started out some time ago with a paper containing a very spirited, but in my opinion more emotional than scientific, defense of the Marshall and Sanow studies after the latter came under criticism, particularly in this rather scathing analysis by Duncan MacPherson; It is essentially a statistical critique of the Marshall and Sanow conclusions.

http://www.firearmstactical.com/marshall-sanow-statistical-analysis.htm

Some of the theorems proposed by Marshall and Sanow were also criticised in this report, prepared by FBI Special Agent Urey Patrick.

http://www.firearmstactical.com/pdf/fbi-hwfe.pdf

The FBI report describes the physiological mechanics of handgun wounding and lethality; it attributes handgun bullet effectiveness to shot placement, penetration and to a lesser extent, to bullet diameter; it indicates that the idea of the reliable one shot stop is a myth; and it discounts the effects of energy transfer in handgun loadings commonly used in law enforcement and self defense.

Also, the FBI report points out, quite correctly, that there are so many variables in handgun wounding (bullet shape, mass, velocity, and construction, how many hits, point of entry, angle of entry, whether the bullet(s) hit an arm, clothing worn, what the bullet hit inside the body, the physiology and condition of the person shot, and so on and so on), that it would take an extremely large database--more than would ever be remotely possible--to draw reliable conclusions about the effectiveness of different handgun rounds on humans.

Many of us have grown up reading about "hydrostatic shock" (that's a misnomer, and I should have known that when I was studying college physics while reading Jack O'Connor's discussions about the subject). Some of us may have assumed accordingly that a handgun that kicks more than others and makes more noise, or that one that really does a number on a gallon jug, will be more effective in self defense. Some of us may have read stories about the old .38 Long Colt and the Army's insistence on a .45 for their first automatic, without realizing that the effectiveness of the bullet on the enemy's horse was really what the Army was concerned about. I'm guilty on both counts.:)

Based on what I (think I) know now, however, I'll stick with something I can control in very rapid shooting. I've never shot anyone and I've never seen anyone else do so, but I put a lot more importance on how well I can do with a particular gun in training than on muzzle energy, and I'll put a lot more credence on the FBI report than on the paper of a couple of people who seem to have a need to attack anyone who questions the conclusions of Marshall and Sanow.

9mmforMe
November 16, 2010, 01:19 PM
Well put Kleanbore...I think your conclusion is quite reasonable and I feel comfortable adopting the same position until I see otherwise.

A.H. Fox
November 16, 2010, 01:37 PM
How big a factor do you think it is?
I have heard that in VT they hunt pike with firearms, shooting down into the water over the pike coming into the shallows and recovering the stunned/dead fish, so there it must be a factor.
However, any shot into the chest cavity will be into largely air lungs, probably not a good medium for transmitting shock waves.
I am not a hunter, or a physicist, just curious.
Yes I did do a search before posting.
Thanks in advance.
Hydrostatic?...try hydrokinetic.

The projectile induces motion in the fluid (tissue). The tissue does not stay at rest after impact. There fore hydrostatic is not an accurate representation of the physics involved. The shock comes from the motion induced after projectile impact and the energy transfer to surrounding tissue.

therewolf
November 16, 2010, 02:17 PM
IMO, it's the slower, fatter pistol round which makes the .45ACP so effective as an anti-personnel round.

It's less likely to pass on through a person, and all the terminal energy is absorbed by the body, in that case. How much of that is actual hydroshock is still conjecture, however.

The FBI, who have done many of these ballistic studys, BTW, seems to favor the .45ACP in their field weapons...

When I was in high school, we used to shoot into soaking wet telephone books, at that time, this was the closest thing they'd found to the texture of a human body for ballistics penetration tests.

Kleanbore
November 16, 2010, 02:59 PM
Posted by therewolf: MO, it's the slower, fatter pistol round which makes the .45ACP so effective as an anti-personnel round.That may be true in military applications in which FMJ bullets may be used, and I bought a .45 on the basis of that belief, but it now seems that the idea that the .45 is markedly superior to, say, the 9MM, is no longer held in many informed circles. That's been the subject of a lot of debate here.


It's less likely to pass on through a person, And that's a good thing.

...and all the terminal energy is absorbed by the body, in that case.In the FBI report linked in a previous post above, the statement is made that energy transfer is not a major factor in handgun wounding effectiveness.

The FBI, who have done many of these ballistic studys, BTW, seems to favor the .45ACP in their field weapons...While the FBI has reportedly procured a small number of special Model 1911 pistols for SWAT teams and for hostage rescue teams, the standard issue weapons are Glocks in .40 S&W. The U. S. Marshal Service also uses the .40 S&W. The Secret Service standard issue these days is the .357 SIG.

Back in earlier days, the FBI used a number of Smith and Wesson .357 Magnum revolvers. What they were after was greater penetration--not to go through the body of an opponent, but to penetrate car bodies.

KodiakBeer
November 16, 2010, 04:29 PM
It's less likely to pass on through a person, and all the terminal energy is absorbed by the body,

A myth. One might twist this into an argument in the case of two projectiles of varying diameters, but assuming the same diameter - the projectile passing through the body imparts more energy. The projectile that stops didn't have enough energy to pass through.

It's like being stabbed with a 6" knife and an 18" knife. The longer knife does more damage.

.

Full Metal Jacket
November 16, 2010, 05:56 PM
A myth. One might twist this into an argument in the case of two projectiles of varying diameters, but assuming the same diameter - the projectile passing through the body imparts more energy. The projectile that stops didn't have enough energy to pass through.


energy makes a difference in wound ballistics with powerful rifle rounds, and to a lesser degree with the upper end of handgun calibers (44mag through 500mag).

with the popular self defense calibers (9/40/45), it makes no difference. for these calibers, penetration and expansion diameter are the important factors :)

KodiakBeer
November 16, 2010, 06:18 PM
with the popular self defense calibers (9/40/45), it makes no difference. for these calibers, penetration and expansion diameter are the important factors

Yeah, I'm just referring to the popular (and silly) notion that a bullet stopping within the target "imparts all of it's energy" and hence is a desirable trait. While it does indeed "impart all its energy", the same bullet traveling the same path at higher velocity and exiting, imparts even more energy since it requires more energy to travel further through the tissues.

If the myth were true, the secret to great bullet performance would be to simply download all handgun cartridges to 500 fps (or so), so they'd always stop in the body and "impart all their energy".

.

therewolf
November 16, 2010, 06:24 PM
I suppose everybody also has a glib explanation for why our front line soldiers seem to all prefer 45 ACPs to the issue 9MMs.

Many have even gone so far as to have a 9MM they use in inspections, then take a .45 into the field.

RBH44
November 16, 2010, 07:09 PM
For some interesting reading on this subject and other Terminal ballistics go to www.frfrogspad.com and click on the "Treminal ballistics" page.

Shadow 7D
November 16, 2010, 07:11 PM
Hate to say it, but NO, you don't play with un-issued weapons that gets you into bad juju in the US Army, been there, done that, seen my friend busted for trying to sneak his AR over (different unit, but it was weird to out rank him)

OH, and there is this funny thing, bet you didn't know, it's hard as hell trying to get the issued 9mm to work in a .45, and supply doesn't just give ammo out, donchaknow????

So sorry therewolf, but you need to back up that damn rumor

Shawn Dodson
November 16, 2010, 10:29 PM
See post #2 of this thread (http://www.m4carbine.net/showthread.php?p=411452#post411452) regarding the Courtney paper "Scientific Evidence for Hydrostatic Shock".

Another pearl of wisdom - http://www.m4carbine.net/showpost.php?p=411817&postcount=164

Shadow 7D
November 16, 2010, 11:52 PM
Oh shawn, why do you have to do this every time, dropping science and/or commonscence where people are so emotionally invested.

I mean, hell, I just tell everybody that I think .45 (the round) is ugly, I just don't like the proportions...

Full Metal Jacket
November 17, 2010, 12:40 AM
Yeah, I'm just referring to the popular (and silly) notion that a bullet stopping within the target "imparts all of it's energy" and hence is a desirable trait. While it does indeed "impart all its energy", the same bullet traveling the same path at higher velocity and exiting, imparts even more energy since it requires more energy to travel further through the tissues.

right. a 9mm imparting all it's energy into a target makes no difference....a 50BMG is another story lol :)

JTHunter
November 17, 2010, 12:52 AM
For all that has been posted here, the one thing that I haven't seen anybody mention is that this "hydrostatic shock" is also know as "depth charges"! :D
Haven't any of you as a kid ever thrown a "cherry bomb" or other sizeable firework in the water and watched the fish float up when it goes off? :evil: This is why most states outlaw "dynamiting" for fish as it IS so destructive and indescriminate.

Shadow 7D
November 17, 2010, 02:03 AM
Right, now show me your fluid filled jelly sack, or your water jug organ
and Ill throw the cherry bombs at you

millertyme
November 17, 2010, 02:08 AM
Many have even gone so far as to have a 9MM they use in inspections, then take a .45 into the field

Really? And where the the ammo for said .45ACP's come from? And where did they get the pistols to begin with? My cousin was in Iraq for a couple tours (11B) and I asked him this kind of question based on stories we've all heard and some of us have perpetuated about soldiers taking unissued arms into combat. His exact reply was this: "No. The only thing you bring that you aren't required to bring is extra ammo for yourself and extra ammo for your SAW gunner. Every now and then you get some wanabe ninja who brought some big ass knife from back home like he's Rambo or something. We're all like, 'What the hell are you doing with that? You going to get in a knife fight with someone? Where are your weapons when all of this is going on? Why don't you leave that POS behind and just bring extra ammo.'"

Erik M
November 17, 2010, 02:31 AM
How big a factor do you think it is?

A big enough factor that its caused an endless edit war on wikipedia on the 5.56x45 article. People really freak about the ability/claimed inadequacy of the cartridge.

Erik M
November 17, 2010, 02:33 AM
Many have even gone so far as to have a 9MM they use in inspections, then take a .45 into the field. Never seen one strapped to an MP or carried by staff at Wright Patterson in the 2 months I worked there. Pretty sure they don't issue 1911 to infantry anymore either.

Shadow 7D
November 17, 2010, 05:55 PM
Exactly, seen some nice sigs, but those where DA police and contract guards, CONUS
not deployed MP's,

but 'call of duty' is real eh...

Jason_W
November 17, 2010, 06:49 PM
I'm guessing there is more than one factor involved in messing up enough vital tissue to kill an organism. Which factor is most important? I have no idea, though I'm partial to wide, heavy chunks of lead over pointy and speedy.

Millwright
November 18, 2010, 06:43 PM
"Amusing" topic ! FWIW, IMO - an IME - "hydrostatic shock" can effect a lot things at far remove from the body cavity of game animals. And much closer to home, too !! Now for some personal, subjective observations......

I used to point shoot a lot of minnows in the creek next to the house. I used .22RF LRHP in a H&R revolver with a six inch barrel. I would note a "cone" spreading downward from POI -before the inevitable "splash". If the minnow was in the cone he floated up......Larger fish like carp had to be hit directly ! But I've noted a big bore/high-velocity rifle can have the same effect upon large fish close to the surface as well.......BTDT.....

"Hydrostactic shock" is also the same effect making water pipes hammer, or hydraulic hoses 'jump' when flow is suddenly cut on/off. I expect it has similar effects upon tissue - even when said tissue isn't "homogenuous", like a pile of ballistic gelatin. FWIW, air is compressible and liquids/viscuous semi-solids aren't. Meat kinda meets the latter category IMO/IME. So. When we hit meat we get a 'hydro-static shock wave' then the bullet hits lungs/air and for a nano-second it compresses something, then goes on the hit some more watery tissue.....IOW, IMO most of this 'argument' - regardless of who propounds it - is BS ! >MW

Pyro
November 18, 2010, 06:51 PM
I find these arguments about these "super bullets" causing "hydrostatic shock" to be a load of poo. Not that it's false but IMHO it's redundant to argue.
When you shoot someone they are not going to yell "oh no! hydrostatic shock!"
I'm not saying it's wrong to argue, just a bit silly.

Sevenfaces
November 18, 2010, 06:54 PM
Hydro static shock, as I have interpreted it is vascular damage in locations not hit directly by gunfire (i.e. cerebral hemorrhage after taking shot to the chest)
which I believe they claim is due to cavitation. I'm not too convinced about the studies I have read, or the combat effectiveness/relevency of the phenomenon.

Now cavitation I do believe is a big deal, especially when hitting non hollow organs, such as the liver, where it can cause damage of a much wider degree than .355 of an inch. Cavitation isn't really relevant in most pistol calibers, anything that musters more than 500 ft-lbs will have enough to do damage.
Below that, I don't think its enough to matter.

I want to also point out there is a real condition called Hypovolemic Shock which is caused when your body has a drop in blood pressure due to hemorrhage, either external or internal. Any bullets can cause this kind of shock.

kiwi**
November 19, 2010, 10:24 PM
Asl,slak
[

therewolf
November 20, 2010, 12:14 AM
Kiwi makes an excellent point here. ^^^^^^

Empiric military evidence, garnered from eyewitness accounts from field personnel over the past 75 years, appears, in many situations, to some degree, at some point in time, occasionally,to indicate a general preference of fatter slugs with less penetration, for anti-personnel use in pistol rounds.

Scientific evidence could possibly some day prove or disprove military history, but for now it seems clear that there's divergent opinion over the efficacy of
hydrostatic shock as a major factor in overall ballistic knockdown power.

(and, BTW,2+2 =4)

Shadow 7D
November 20, 2010, 01:17 AM
Knock down power
yeah, you had me going there for a moment

So, how does a 115 GRAIN (less than 3 10ths of an ounce) transfer enough power to 'knockdown' someone, point is, it's a proven psychosomatic response (you drop cause think you are supposed to)

Zoogster
November 20, 2010, 01:47 AM
Not relevant to typical pistol rounds. Pistol rounds work by damaging tissue they come into contact with.
At most hydrostatic effects would seem to be a slight slap to the system.

Rifles are a different story.
But it is still not reliable in typical assault rifle calibers, which is why there is such a big deal made about fragmentation requirements with the 5.56.
They are still too weak.
You have to get into the full power rifle rounds before it is worth really considering.


FMJ said:

i think the 6.8 would be a much better US military round--better penetration, more energy, stable at longer distances, and not much bigger than the 223 so soldiers can hump the same amount of ammo around.

The British thought so too over 60 years ago when they were fielding the .280 British (basically the same thing as the 6.8.)
The USA told them no, Americans don't use such wimpy 'poodle shooter' rounds, if it is under .30 it is unsuitable to replace the .30-06. Americans went on to use the 7.62x51mm and M14 before reverting down to the 5.56x45mm a short time later.
What people suggesting the 6.8 as an improvement today are really doing is saying the British were right all along over 60 years ago and that the .280 British should have been adopted as the NATO standard 60 years ago.

Erik
November 21, 2010, 12:43 AM
"How big a factor do you think it is?"

I'm torn between (1) it isn't and (2) not much, if at all. Take your pick.

Ragnar Danneskjold
November 21, 2010, 12:52 AM
Troops have been asking, with partial success, to get the larger bore 1911A1- .45 caliber ACP back in service, for the simple fact that the 9MM rounds don't put a determined attacker down every time on the first shot. The 45 caliber 1911A1 has a strong reputation for having a large enough projectile to do this effectively.

If you are expecting any handgun round to put down any attacker every time with one shot, you are an idiot. I hate to put it that way, but the "one shot stop" method for determining which caliber performs best is probably the absolute worst way to do it.

The 9mm is a great combat round for the simple reason that it is easier to shoot, gives the soldier more chances to hit targets, and more chances to hit vital areas on those targets. Any pistol that only gives you 8 rounds of anything is a bad combat handgun. And as an MP, yes we use our pistol in conjunction with our M4 all the time, so yes the M9 gets a good deal of use. This deployed troop will always choose 16 chances to put lead through an insurgent's spine over 8.

Running through a building with an inop M4 and an empty pistol is a bad time to realize those big heavy rounds you ran out of while shooting at multiple enemy fighters might not be as awesome as you thought, especially if some of them were misses (and most probably were). I'll take a pistol that give me more chances and more hits every time.

As for the "9mm for inspection, .45 in the field" idea, I'm calling BS on that. Non issue weapons are prohibited in every way, and I have yet to meet a soldier will to risk getting caught running around outside the wire with a 1911 strapped to his thigh. The most I've seen is an AK or two stashed in the turret or back of a vehicle. But actually bringing over and using an 1911? Save the tall tales. That stuff doesn't really happen in real life.

Adios for now, from somewhere in A-Stan.

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