Hydrostatic Shock

[svtruth]

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.

 

[papa_bear]

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]

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]

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]

Ever wonder why the .357 MAG 125gr. HP is so effective?

 

[fastbolt]

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]

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]

The research suggests it's more important than it is not.

 

[papa_bear]

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

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

 

[robertbartsc]

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]

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]

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]

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]

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]

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]

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]

anemic 5.56 shock....

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

 

[Full Metal Jacket]

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]

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]

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]

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]

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]

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]

"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]

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.