Hydrostatic Shock (pistols)

[Frank Ettin]

..."It hurts, how did I get on the ground? What happened, am I dead? How can it hurt this much? I feel like puking."

That's how I would feel if my chest exploded inside. This is similar to the kicked-in-the-balls effect....

But in fact, often one or more solid, center of mass hits with powerful handgun rounds will not drop the assailant. Not infrequently there will be no, or minimal pain, due to the effects of adrenalin or drugs. These are well studied and well documented phenomena. If you're genuinely interested in this area, you might do well to do some studying rather than simply relying on your imagination.

 

[JohnKSa]

Because the water is non-compressible. But that is still very different from the energy of a penetrating projectile acting on a non-compressible medium (the water in the body) contained in a deformable medium (the tissues of the body). In your jug, the energy of the penetrating projectile is transferred directly to the support by the non-compressible water. In the body, much of the energy of the projectile is dissipated in the deformation of tissue.

The point remains that water (which is mostly what we're made up of) can transfer significant energy from the wound channel to points that are remote to the wound channel.

That still leaves two questions:

1. How much energy is transferred?
2. Can that energy do anything "useful" and if so, how "useful"?

It's true that most of our tissue is not affected much by a reasonable amount of deformation, but it's also true that certain parts of the body have a very poor tolerance to being stretched. The liver is a prime example.

I think that one thing that gets lost in these discussions is the distinction between: "not a reliable wounding mechanism" and "non-existant". Clearly not all of the tissue in the body can deform significantly without damage and clearly water can transmit significant amounts of energy.

Is that something we should count on? No, but that's not really the same as saying it doesn't exist at all.

 

[Frank Ettin]

...It's true that most of our tissue is not affected much by a reasonable amount of deformation, but it's also true that certain parts of the body have a very poor tolerance to being stretched. The liver is a prime example....

And that adds yet another variable -- shot placement.

...I think that one thing that gets lost in these discussions is the distinction between: "not a reliable wounding mechanism" and "non-existant"....

Absolutely. However, as I recall the OP's original question it was something on the order of: Is there a common handgun cartridge that will produce sufficient energy such that the hydrostatic shock produced by a hit to the thorax could reasonably be expected to cause instantly incapacitating damage to the brain?

And I'd suggest that the answer is something on the order of: It appears that there is no evidence that hydrostatic shock produced by any handgun cartridge usable in a gun reasonably suitable to be carried for routine self defense applications can produce disabling brain damage from a thoracic hit.

 

[tipoc]

And I'd suggest that the answer is something on the order of: It appears that there is no evidence that hydrostatic shock produced by any handgun cartridge usable in a gun reasonably suitable to be carried for routine self defense applications can produce disabling brain damage from a thoracic hit.

That's the answer to the question.

By whatever name it's called, hydraulic shock, pressure wave, hydro static shock, etc. the phenomena exists and has been recorded and described. It's results are most often seen in shrapnel wounds and in wounds from rifle rounds. It is mostly localized in pistol rounds if and when it is a factor at all. It is a factor in wound trauma.

However you can't count on it for anything. There are too many variables. You can count on shot placement and the right caliber for the job.

tipoc

 

[TEX]

Don’t know if this really applies, but from experience in hunting deer and hogs, almost with exception those I hit in the chest area with bullets moving over 3,000fps (at point of impact) went down and did not get back up or move again. Real life DRT. I have a 270 load that leaves the muzzle at almost 3,200fps and at short ranges, 50 yards or less, it has always had this effect with the animal if hit behind the shoulder in the chest cavity. Seen perhaps a dozen or more go down this way. I don’t know that hydrostatic shock causes brain damage, but I do think it can have the same effect as the blood pressure in the brain suddenly increasing and the body’s response being to open all the blood vessels to lower the pressure and by the time the brain figures out the pressure isn’t going to stay high, the animal has expired. Just my observation and WAG. I have heard, but never seen, the idea that if you hit someone hard enough in the side of the neck it will cause the person to momentarily black out due to the same thing (temporary high blood pressure that causes the blood vessels to dilate. I don’t think any pistol round can approach this although very fast moving 357Mag rounds have built a reputation of putting bad guys down pretty fast if placed well. I had a Texas DPS officer who was in on the caliber selection process tell me that one of the reasons they went from 45ACP to 357Sig was that the 45ACP was NOT giving them the “stop them right now” quality the old 357Mag gave them and it wasn’t punching through car doors, windshields, etc. like the old 357Mag. IMHO, the 357Sig just barley reaches the lower end of what the 357Mag could do.

 

[LaserSpot]

Yes, a .270 has plenty of power to produce hydrostatic shock. Some of the more powerful types of handgun ammunition can too, but not as reliably. Unreliable doesn't equal undesirable; why not choose ammo optimized for the "stop them right now" bonus, but keep shooting accurately in case it doesn't work?

The "hydrostatic shock" effect is pretty well documented; we just don't know how it works. Everyone has a different guess. Here is mine:

If you've seen the inside of an animal shot with a high-powered rifle, you know that it often looks like a bomb went off. I think that this internal explosion must be painful. Not the excruciating, unbearable, please stop, type of pain. More of a sudden, unimaginably overwhelming, disorienting pain; maybe something like being tazered.

All that simultaneous tissue deformation and destruction must send an enormous number of neural impulses to the brain, probably more than it can process. This neural overload causes several seconds of immediate incapacitation, often followed by rapid blood loss.

 

[MCCALL911]

Here's a few questions I have which may, or may not, relate to hydrostatic shock. I'm just trying to wrap my head around the concept.

Suppose you have two bullets which have impacted a target with 2000 ft-lbs of kinetic energy. Bullet #1 penetrates to a depth of 1 foot (12 inches.) Does this not mean that the resisting force of the target has been 2000 pounds? Now we have bullet #2 with the same KE which penetrates to a depth of 2 feet (24 inches), does this not mean that the resisting force has been 1000 pounds?
If this is true, then won't bullet #1 cause a greater amount of damage and disruption in the target, despite the lesser penetration?

 

[tipoc]

Suppose you have two bullets which have impacted a target with 2000 ft-lbs of kinetic energy. Bullet #1 penetrates to a depth of 1 foot (12 inches.) Does this not mean that the resisting force of the target has been 2000 pounds?

Here I'm not sure what you mean by "resisting force". As you know some materials are denser, or harder, or in some way more resistant to a penetrating bullet than others. A tougher material will force a bullet to transfer energy at a higher rate, this will slow penetration. Oak is harder than pine, for example. Most energy transferred to the struck object is no longer kinetic energy but potential energy. In any case the struck object will not absorb all the energy of the bullet in some way in an equal trade off. Neither will the struck object expend energy in slowing the bullets path.

If what you suggest were true than if I fired a bullet into the ground it would not penetrate at all because the "resisting force" of the bullet is many times greater than the energy of the bullet.

So the answer to your question above is , No.

If we have two bullets of equal design, ball ammo let's say, shot into similar objects penetration will be similar. If there is a significant difference it's due to differences in the material shot into.

tipoc

 

[brickeyee]

Suppose you have two bullets which have impacted a target with 2000 ft-lbs of kinetic energy. Bullet #1 penetrates to a depth of 1 foot (12 inches.) Does this not mean that the resisting force of the target has been 2000 pounds? Now we have bullet #2 with the same KE which penetrates to a depth of 2 feet (24 inches), does this not mean that the resisting force has been 1000 pounds?

Averaged over the whole bullet path, work delivered equals ft-lbf/feet travel.

The problem is that the force is NOT delivered uniformly since the target does not have a uniform resistance.

If all you want is the average force delivered it divides out.

The RATE of energy loss has a lot to do with the damage that will be done though.

 

[AK103K]

You boys can worry the figures and data all you want. If a round blows things up when I shoot it, works for me, and I dont care why.

Then again, if you get out and actually shoot living things with your magic bullets, you'll know what does what (or doesnt) in the real world, regardless what the paper says should (or shouldnt) happen.

 

[NightSleeper]

Hydrostatic Shock is a myth, even for high powered rifles.

Agreed, and I thought it was debunked by now.

The fabelled "One shot stop round" is also a myth (no offense to you .357 and .45 lovers). People who get hit with a large bullet do not "just fall down" (common myth about the good ole' .45).

So is "immediate incapacitation". Unless it's a headshot, or base of the spine, a person getting shot will not be "incapacitated" due to the wound. Not even a shot to the heart will do this (although odds are he'd be dead within minutes). The only thing that actually incapacitates a person who's been shot is actual shock -- that is, their mind going hazy because of the trauma. Not all people suffer from shock after getting shot.

I read an interesting report by the FBI about this. It was published in 1989 I think. The author makes a point to debunk the whole "one shot stop" and "immediate incapacitation" theories when it comes to calibers, bullets, etc. Granted, a lot of new self defense rounds exist now that didn't then, but I tend to be skeptical when it comes to these new "myth buster" bullets.

 

[MCCALL911]

Here I'm not sure what you mean by "resisting force".

Hmm...I didn't realize that resisting force was such a vague concept. If you step on the brakes of your car, is that not the resisting force to its motion?

If what you suggest were true than if I fired a bullet into the ground it would not penetrate at all because the "resisting force" of the bullet is many times greater than the energy of the bullet.

Where exactly did you get all that nonsense from what I wrote? I thought my brief series of questions was reasonably simple and clear. Guess not.

I think what I want to know is answered here:

http://mcasco.com/qa_marf.html

Averaged over the whole bullet path, work delivered equals ft-lbf/feet travel.

It was the pounds of force that caught my attention. Foot-pounds of KE divided by distance travelled in feet is pounds of force. I thought that this was significant in some way.

 

[tipoc]

Sorry my sentence was unclear it should have been:

"If what you suggest were true than if I fired a bullet into the ground it would not penetrate at all because the "resisting force" of the earth is many times greater than the energy of the bullet."

The way you wrote the question (or the way I read it) implies the existence of some type of resisting energy that springs up or is transferred from the bullet to the thing being struck. Or that the energy required to stop the bullet is equal to the energy of the round. But it does not work like that.

In the case of the brakes you mentioned energy from the forward momentum of the vehicle is transferred to the brake pads and is mostly seen as heat. As Brickeye pointed out the rate of that transfer is greater or lesser depending on the object being hit or bullet construction. Hollowpoints are designed to transfer energy faster.

Could be I don't understand your question. Or there is a confusion of terms a "pound ft of force" refers to torque while a pound ft of energy is used to measure ke. Maybe the force threw me off.

Over here http://mcasco.com/qa_marf.html what they show is; if we know the weight of an object and it's velocity and we time it's flight from the moment it strikes and object to when it's forward movement ends, we can figure the rate of energy transfer. And figure how much resistance it met each inch along the way, provided the object had even density.

tipoc

 

[MCCALL911]

we can figure the rate of energy transfer.

OK, I understand now. We're all apparently talking about the same thing, just tripping over each other's terminology thinking it means one thing when it means something else. I beg your pardon.

It turns out that the "resisting force" (my terminology and the one in that website) appear to be the same thing appear to be what brickeyee refers to as "work."

So I won't add to the confusion. I'm confused enough myself.

 

[tipoc]

I confuse myself too.

There is an excellent book available by Robert A. Rinker called "Understanding Firearm Ballistics" that helps unconfuse me sometimes. It's worth the price and is available new and used at the regular places online.

tipoc

 

[tipoc]

Back to the topic...

Hydrostatic Shock is a myth, even for high powered rifles.

Agreed, and I thought it was debunked by now.

Actually it's not a myth and what's always been debated , and still is, is how much of a factor it is in wound trauma and how reliable a factor it is in stopping.

I could quote some here from Col. Chamberlain or from P.O. Ackley but Robert Rinker is in front of me, so, pgs. 336-337:

"The exit wound, then is not a mere puncture, but an explosive release of the wave before the bullet has reached the surface. This was shown by high speed photography as far back as World War Two.

"A well known theory states that a high velocity impact creates a hydraulic action in the body that disrupts the blood vessels and other body parts that are yielding. This action effects areas of the body not directly impacted by the bullet. The high velocity and abrupt shock also increase nerve and bone damage. The effect is strongest at velocities at and over about 3,000 f.p.s.
This is most pronounced in areas of the body that are primarily water like...The force is outward and in all directions...This is sound reasoning and no doubt has an effect on the outcome. It remains to be discovered or proven exactly how much...

"Some experts disagree on the end result...In all probability, the end result would depend on many variables and be unpredictable."

That's what we are speaking of. The idea that you can shoot a deer in the thigh and cause it's brain to blow out it's eyeballs is an old saw. But that a high powered rifle round (or fast shrapnel) can liquefy the area around the path of a bullet, distinct from the temporary wound channel is most certainly true.

In either case there is no substitute for a well placed shot with the right caliber for the job.

tipoc

 

[LaserSpot]

I read an interesting report by the FBI about this. It was published in 1989 I think. The author makes a point to debunk the whole "one shot stop" and "immediate incapacitation" theories when it comes to calibers, bullets, etc.

I would like to read that. For training purposes, it makes sense to assume (and tell the students) that your target will always require multiple rounds to put down. No practical handgun has enough power to reliably drop a man with one shot, especially if he's numbed by drugs or adrenaline.

For defensive ammo selection purposes, it's better to look at what really happens and buy the one-shot-stop stuff, even if it doesn't work that way every time.

On the other hand, if you're going to try and hunt heavy game with a handgun, the priorities are different. You need reliable one-shot lethality, but don't have to drop the animal in its tracks. If it keeps going for 30 seconds, your hunt is still successful. In this case, I would look at heavy lead flat-nose ammo like Buffalo Bore sells. It will break bones and drill a good sized hole right through the target. It's also perfect for you "Hydrostatic shock is a myth" guys.

 

[shep854]

The FBI report mentioned is likely the report on the 1986 Miami Shootout, where the perps kept fighting after receiving several mortal wounds. Prior to this, the shock theory prevailed. However, the autopsy of one of the shooters showed that one of the 9mm bullets stopped just short of his heart, causing a mortal wound, but not immediately incapacitating.

In the aftermath, FBI tests determined that penetration was the most critical factor, not "shock".

See: http://en.wikipedia.org/wiki/1986_FBI_Miami_shootout

 

[NightSleeper]

In the aftermath, FBI tests determined that penetration was the most critical factor, not "shock".

Correct. I believe they require a minimum of 12" of penetration. As to the actual report, I read it off one of these gun forums. Do a search for "FBI ballistic reports" or something. I'll see if I can find it.

 

[Ar15M4]

Sounds like there are a lot of people here watch too many movies and think that you can "take out the bad guy" with one well placed bullet from a pistol.

Force is Mass times acceleration. There is a specific harmonic frequency which your brain and nerves work. Hydrostatic shock is a real thing just as the computer screen you are looking at.

Simply stated it is a remote neural wounding of the brain or CNS (central nervous system) due to the impact of a projectile in living tissue that causes a hydraulic effect in liquid filled tissue.

I am not going to talk specifics of my job or how / why I have this info. It is basically shock to the brain or brain stem. You see it in vehicle collisions when someone is killed by a foreign object during the collision. Or sometimes we see it when someone falls from a height that is not high enough for them to reach terminal velocity. Or sometimes just when they hit the steering wheel. It really has more to do with the individual and their BMI, and if they retain water, etc. than it does with which bullet you shoot them with.

I can say that I have seen a man (granted he was high on drugs) take more than 50 rounds of ammo to the thoracic and abdominal cavities and still beat an officer almost to death with a wheelchair.

So if you are talking shots from a handgun to a body that isn’t high on drugs. I guess it is theoretically possible. Though it may or may not be feasible.