Hydrostatic Shock (pistols)

I think some people are confused about terminal ballistics and exactly what hydrostatic shock is.

Bullets create a permanent cavity in the target. That is, the bullet will crush and destroy the tissue in its direct path. When the bullet hits the tissue it acts much like a fluid. Pressure waves tend to distort the tissue. This causes a temporary cavity as the tissue stretches and deforms. These pressure waves can propagate at nearly the speed of sound. Many things such as bullet design, sectional density, velocity, and even the target itself effect cavitation. Hydrostatic shock occurs when the tissue is stretched so far that it begins to tear. Generally speaking, handgun bullets do not posses the energy required to deform tissue beyond this elastic limit.
 
"Bullets create a permanent cavity in the target. That is, the bullet will crush and destroy the tissue in its direct path."--44Magnum

And even that is subject to conditions. For FMJ ammo, the permanent wound channel will usually be less than the bullet diameter, due to the aforementioned tissue elasticity. This is why semi-wadcutter bullets make good hunting bullets; they have good penetration due to weight, and the shoulder cuts tissue instead of pushing it aside. Before effective HP bullets, Jeff Cooper recommended SWC bullets for the .45 ACP. This cutting feature is also why some suggest .38Spl 148gr full wadcutters for SD.
 
It has always been my understanding that a good hit that breeches the chest cavity will cause the lungs to collapse, and if there is significant damage to major arteries, these 2 conditions causes a sudden, sever drop in blood pressure, which has a dramatic effect on immediate brain function.
 
Theories of hydrostatic shock have been around since the advent of smokeless powder. The appearance of the latter allowed for rifle rounds to achieve speeds unheard of before. The small and fast vs. slow and heavy debate took off among long gunners. Hydro static shock theories (sometimes called ballistic pressure waves, etc.) were part of the effort to explain why the 22-250 could kill a deer as dead as the 30/40 Krag even when the early light bullets did not fragment to pieces. It was an attempt to explain why some rounds at close to 3000 fps seemed to liquify meat in the vacinity of the wound even when the bullet did not break apart.

In the post war period Col. Frank Chamberlain of the U.S. Army and others conducted extensive tests on rifle ammo for the military on wound effectiveness. This was the first systematic efforts to record and describe such shock. They described it and discussed it. They identified it as a factor in damage from rifle rounds. Sometimes they found the damage could bruise tissue remote from the direct path of the bullet, sometimes it could break bone, sometimes no visible damage. The extent of the damage varied on a variety of factors and combinations of them. So much variation was present that the effects of hydrostatic shock (a name that predated their study) could not be relied on as always a factor in terminal ballistics.

Dr. Michael Courtney and others have conducted some ongoing research in it under the name ballistic pressure wave.

There has been some research suggesting that some bullets hitting some areas of the human body can momentarily disrupt the blood in arteries and veins remote from the area of bullet impact and cause some disputed amount of damage. That is the extent of the research though. It is not enough to draw any conclusions from. No one suggests that this can kill.

This research is of some use in terms of bullet design and treatment of wounds. It does not effect anyone interested in defensive handgunning or handgun hunting.

tipoc
 
Correction, the speed of sound in tissue is approximately 4500 fps. In other worse, hydrostatic shock is impossible in just about every gun in civilian hands.
Click to expand...


I do not think anyone believes it is a full up shock wave from exceeding the speed of sound in the medium.

A better name might have been 'hydraulic shock.'

The 'hydrostatic' portion comes from the fluid not moving, but transferring a pressure wave (and not necessarily a shock wave) that creates additional shock in the victim.

There are some real possibilities that some effect may be present.
It does not take very much pressure to interfere (even temporarily) with nerve function.

Bump your 'funny bone' (ulnar nerve on the outside of the elbow) and see how well you hand works for a brief time.

Pinching nerves can not only be painful, but can prevent normal nerve function (numbness being a common affect on sensory nerves, and p[aralysis on motor nerves).

Used in this manner the term has a long history.
 
One of the names it has gone by is hydraulic shock. As i mentioned the idea is close to a century old. Various names have been used by hunters and shooters over that time. Has nothing to do directly with the speed of sound.

tipoc
 
If were going down this road the go with a M1A1 or M1A2 each comes with a 120 mm barrel (just short of 5 inches, in width) and shoots with 195,000 lbs per square inch behind it.

http://www.globalsecurity.org/military/systems/ground/m1a1-pics.htm

I personally guarntee it can and does generate massive Hydrostatic Shock and you wont need to worry about brain damage as you will need a sponge for the residue and maybe a baggie or two.

Makes those 50 cals just plain insignificant, but I dont recommend concealed carry with it. Other than that IMHO I just wouldnt wont worry about Hydrostatic Shock, as marksmanship and reaction time and awareness will consistently and reliably benefit you more than Hydrostatic Shock.

Just for the record this is all tongue in cheek, but I do believe my point is valid.



:p
 
Last edited:
"I never thought it would happen. I have found a topic about guns and shooting that has completely bored me."--twhidd

Read about benchrest shooting.;) Unless you're one of them, you'll be out before you know it.:p
 
If the human body was a "water tank" that was sealed off you could expect hydraulic type shock thourought the body, but being muscle and bone I just cant see it. Things are going to happen...there will be shock(trauma type) and one person may blackout while the next person gets an adrenaline rush. Since our bodies arent sealed and pressured up to an initial 100 psi, you cannot apply Pascals law. I think hydrostatic and "hydraulic" types of shock on the human body are myths, but thats just one mans opinion. If it were true, you might expect a man shot in the chest with a 30.06 to have an eyeball blow out. <-- ok now that was overblown :)
 
Back up, you can't assume that shock is only caused by brain damage, tissue destruction, or a certain level of hydraulic pressure. If someone sucker-punched you in the gut, you might fall to the ground and go into shock. After the guy finishes you off and they do an autopsy, they probably won't find much evidence to prove the shock effect; that doesn't mean it didn't happen. If a fist can do this, why can't a bullet?
 
LaserSpot said:
...you can't assume that shock is only caused by brain damage, tissue destruction, or a certain level of hydraulic pressure. If someone sucker-punched you in the gut, you might fall to the ground and go into shock. After the guy finishes you off and they do an autopsy, they probably won't find much evidence to prove the shock effect; that doesn't mean it didn't happen. If a fist can do this, why can't a bullet?
Click to expand...
There's a huge physiological difference between the effect of significant blunt force trauma to a dense nerve cluster and the penetrating trauma of a small diameter particle traveling at high (relatively) velocity.
 
Maybe so, but a bullet can produce both at the same time. I once shot at a jug of water; not only did the jug blow up, but it cracked the board that the jug was sitting on. I would call that a blunt force trauma.
 
LaserSpot said:
Maybe so, but a bullet can produce both at the same time. I once shot at a jug of water; not only did the jug blow up, but it cracked the board that the jug was sitting on. I would call that a blunt force trauma.
Click to expand...
First, a distinguishing characteristic of blunt force trauma is that it in non-penetrating. Second, see Rayndeon's comment in post 55.

In any case, study the material at the links that Rayndeon has provided. It wouldn't hurt you to study the material at the link that mavracer posted in post 40 or the material at the link that Glenn E, Meyer posted in post 16.
 
FYI:

"In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a body part, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma. The term itself is used to refer to the precursory trauma, from which there is further development of more specific types of trauma, such as concussions, abrasions, lacerations, and/or bone fracturing. Blunt trauma is contrasted with penetrating trauma, in which an object such as a bullet enters the body...." (http://en.wikipedia.org/wiki/Blunt_trauma)
 
The board wasn't penetrated, just cracked like I hit it with a baseball bat; this was from the downward force of the water. I was using a 30-06, but some handguns can blow up a milk jug pretty well too.

I'm not saying that this is my new theory of "hydrostatic shock". The effect that the OP was looking for would be better described as "Immediate Incapacitation", and he asked if it can be caused by remote brain damage from "hydrostatic shock".

I think we can agree that hydrostatic shock is not going to cause lethal brain damage, but could it cause immediate incapacitation through some other mechanism? Psychological effects like this can't be easily predicted with a mathematical formula, but it's well accepted that some types of handgun ammo have more "stopping power". The punched-in-the-gut effect shouldn't be ruled out as a possible means of incapacitation just because it's hard to define and measure.
 
LaserSpot said:
The board wasn't penetrated, just cracked like I hit it with a baseball bat; this was from the downward force of the water....
Click to expand...
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.

There are basically four ways in which shooting someone stops him:

[1] psychological -- "I'm shot, it hurts, I don't want to get shot any more."

[2] massive blood loss depriving the muscles and brain of oxygen and thus significantly impairing their ability to function

[3] breaking major skeletal support structures

[4] damaging the central nervous system.

It's been reported that the majority of "stops" come from the first cause -- the assailant doesn't like being shot, it hurts; and he doesn't want to get shot any more. So he gives up or runs. But while this may be the most common way in which a fight gets stopped, it's also rather uncertain. Adrenalin or drugs can blunt the effects of pain, and people have continued to fight when severely, or even mortally, wounded.
 
Here's one more:

[1b] psychological -- "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.
 
You must log in or register to reply here.
Back
Top