Hydrostatic shock

[rbernie]

Tissue expands and contracts when hit by a bullet, the faster the bullet the more the tissue expands. Non compressible tissue like some organs just rip apart instead of stretching. Is this not hydrostatic shock?

The point that I suspect was being made elsewhere is that hydrostatic shock (or whatever it's properly called) is not a reliable wounding mechanism because different tissues have differing elasticity. As I've heard it said, the key organs that you need to damage/destroy to effectively kill something are fairly elastic and do not react strongly to the pressure wave created by the projectile.

 

[Tactical Rancher]

There is a severe problem with terminology in this thread.

hydrostatic - relating to fluids that are NOT IN MOTION

shock wave - a pressure wave traveling FASTER than the speed of sound

When a bullet impacts a target, a pressure wave is applied, but unless it is traveling faster than 5,052 ft/s (sonic speed in salt water), it will not cause a shock wave in tissue; it is simply a strong pressure wave. The tissue is obviously in motion, as evidenced in many videos, so it is not hydrostatic. Therefore, there is no such thing as true hydrostatic shock. There is hydraulic shock, but only with bullets impacting at greater than 5,052 ft/s. What we normally see is simply a very strong pressure wave that creates tissue damage when the psi level exceeds the natural strength of tissue (widely varied, but you could estimate 500 psi).

 

[starkadder]

Mea Culpa

You are right about the terms being wrong, I did some reserch and "pressure wave" would be the proper description, but the effects are still the same as I described, I have seen the effect of this "phenonenon" on animals and the effects should be similar on a human body. If you haven't hunted much or you don't hunt at all you may not have seen the real effect of certain rounds on flesh and bone, balistics gell doesn't fully show how a bullet reacts on anatomy.

If you want to see some real balistics tests there is a Army documentery of tests done in the sixties and seventies where live pigs were shot with an array of smallarms rounds, I beleive that it was a joint infantry-medical corps test where the surgeons were to treat the animals after the firing tests. I have seen it before but couldn't find a link to it, this footage shows the effect of most military rounds at the time on any type of GSW from minor flesh wounds to chest cavity and head shots.

This is this! It's not something else, it's this

Don't pull it if you don't plan to use it, and don't use it if you don't plan to kill!

ALWAYS REMEMBER OUR MEN AND WOMEN OVER THERE.

 

[hinton03]

Rifle bullets don't cause such devastating affect due to an expanded temporary wound cavity. It is primarily the fact that they fragment at the velocities that they are traveling, causing multiple small permanent wound cavities (cutting organs, tissue and arteries) in the path of the temporary wound channel, increasing effectiveness.

A good example is an Elk I shot in the brisket head on at 30 yards with a 160 grain Barnes X bullet from a 7 mm Rem Mag. It dropped like it had been paralyzed, but didn't die until I shot it in the head with my pistol. As I field dressed the Elk I could see a permanent wound channel the full length of the body cavity, but not enough damage to drop him in his tracks. I finally found the bullet in a rear haunch, it was almost a perfect X, but one pedal was missing. As I was butchering the Elk I found that one pedal in the spine; that is the benefit of fragmentation; something you do not generally get at handgun velocities.

 

[Shadow 7D]

Exactly, when talking of the damage done by a bullet, the permanent track is what is discussed, the temporary track is kinda like quantum physics, its real, there's lots of theories and every expert will tell you something different.

 

[Chuck Dye]

Try the search engine. If you are brave, include Marshall and Sanow as search terms.

Two years ago, we even managed to attract the attention of actual researchers in the field who posted extensively in

http://www.thefiringline.com/forums/showthread.php?t=249109

http://www.thehighroad.org/showthread.php?t=279872.

The signal to noise ratio suffers at times, but the reading and the links are worthwhile.

 

[thesolidus]

seen first hand the difference in rifle vs pistol.
Seen a .45 hit an arm and just stop at the humerus, seen .38 in the chest miss heart and lung and just cause a hole, seen .22 in the abdomen cause as much injury as a splinter. Ouch, but no perforation, minimal bruising and no organ damage.
On the other hand... Seen a 30.06 into a foot, the x-ray shows an entry, bony impact, then an explosion of bone fragments in the direction of travel ( the primary damage from the bullet at very high speed) and the small bones of the foot outside the .30 inch bullet size were displaced and deformed outward.
Seen rifle shots to the leg with clear expanded cavity on x-ray and could touch and feel the huge hole of missing muscle and tissue, plus more blood vessel damage means more bleeding and in this case
A vascular surgeon consult.
A fast rifle round can explode tissue, bone and organ, and the secondary cavity isn't a mythical big Fiit, you can easily see it. It doesn't have to pop you like a chipmunk to be there but it definately causes more damage.

 

[Shadow 7D]

the temporary cavity is just that, here now, gone later, hitting bone creates more wounding fragments, and high velocity rounds can create a vacuum effect that sucks out soft tissue that makes a bigger hole, but still not "shock wave" effect, more vorticity.

 

[plexreticle]

There is a severe problem with terminology in this thread.

hydrostatic - relating to fluids that are NOT IN MOTION

shock wave - a pressure wave traveling FASTER than the speed of sound

When a bullet impacts a target, a pressure wave is applied, but unless it is traveling faster than 5,052 ft/s (sonic speed in salt water), it will not cause a shock wave in tissue; it is simply a strong pressure wave. The tissue is obviously in motion, as evidenced in many videos, so it is not hydrostatic. Therefore, there is no such thing as true hydrostatic shock. There is hydraulic shock, but only with bullets impacting at greater than 5,052 ft/s. What we normally see is simply a very strong pressure wave that creates tissue damage when the psi level exceeds the natural strength of tissue (widely varied, but you could estimate 500 psi).

I believe this is where the disparity took place in my other post, I'm confusing pressure wave effects with hydrostatic shock.

Thanks Tactical Rancher

------

 

[Tactical Rancher]

No problem! I thought of some additional stuff too. Temporary wound cavities are areas where the tissue strength has been exceeded far enough to cause tearing and destruction. These can be just a lethal as permanent wound cavities if they are located properly, BUT in the case of permanent, the tissue has actually been REMOVED by the momentum of the projectile, so bleed-out can occur more rapidly if the tissue damage isn't enough to kill.

 

[testosterone]

The Strasbourg Tests

Google "The Strasbourg Tests".

 

[Coyote_Hunter_]

Personally, I don’t care what you call it – hydrostatic shock, pressure wave, etc., but it definitely exists. When the target material accelerates beyond the means of the material to hold together all sorts of damage occurs. This is true with small varmints, big game, watermelons, water jugs and so on.

Let me provide a god example of what I’m talking about. I have a Marlin .45-70 and loaded some 460g hardcast to 1812fps. For a target I set up two sawhorses with a 12” wide strip of 3/8” plywood on top. A second strip of 3/8” plywood, longer by about 7”, was placed on top of the first. Then a string of water-filled “Family size” Minute Maid Orange Juice jugs were placed on top of the plywood, touching back to front with the lead jug even with the edge of the top strip. The leading edge of the bottom strip was about 7” back from the top one so that the first jug and part of the second was supported only by the top strip.

When I let loose with the .45-70 all “H” broke loose. Most of the jugs exploded and an autopsy showed the bullet was captured in the 9th jug. What was amazing, however, was that when the lead jug exploded it took out a piece of the supporting plywood the same size as the base of the jug. At the same time the reaction of the jugs exerted enough downward pressure on the plywood that they supporting member of the lead sawhorse broke, dumping the plywood and all remaining jugs on the ground.

We temporarily repaired the sawhorse with a 2x2 and used a single strip of plywood, placing several jugs in the center of the strip. This time we used a Marlin in .375 Win, pushing a 220g Hornady FP to about 2230fps. Once again the lead jug blew a hole in the 3/8” plywood.

For comparison, we fired 350g hardcast at 1100fps from the .45-70. The bullet was the penetration king but did little damage. The lead jug blew up but not as forcefully and most of the rest of the jugs just had caliber-sized holes front and back. We repeated this test three times with similar results, shooting the “survivors” with a higher power rifle before they leaked all the water out.

Anyone that has or has seen prairie dogs or watermelon or water jugs or other targets violently disassembled knows what I’m talking about, jet some still deny that it is “hydrostatic shock”. Call it what you will, some loads cause it, some don’t.

 

[hinton03]

Tactical Rancher: Temporary wound cavities are temporary, thus the name. Any tissue destruction would then be a permanent wound cavity.

I posted a link earlier to to FBI study published on handgun wounding. For anyone interested in this subject I recommend you read it, it is a short read. It basically says that handguns do not produce enough velocity to provide incapacitating wounds in anything except the permanent wound cavity; therefore, choose a bullet that will reliably expand and penetrate effectively or choose a large diameter bullet that will penetrate effectively.

 

[JR47]

Consider hydrostatic shock as similar to your entry into the water in a belly flop. The water seems to "solidify" under you.

Hydrostatic shock, and the entire wounding mechanism study is outdated. With more advanced instrumentation, what was once considered a single phenomena has turned out to be several different reactions. There is an electrical, or neural, component in the wounding of a living creature that is just now beginning to be tracked. There are also local reactions caused by muscle reactions, and soft and solid organ reactions that have yet to be properly explained.

In layman's terms, pistols, with there relatively pathetic energy levels, need to hit the brain, or CNS, for immediate effect. Anything else pretty much allows a fight-or-flight reaction that can last 90-120 seconds.

Until that can be better explained, that's all we really need to know.

 

[Shadow 7D]

Anybody have the dead horse animation, that and a few links would bed this topic

 

[psyopspec]

When I let loose with the .45-70 all “H” broke loose. Most of the jugs exploded and an autopsy showed the bullet was captured in the 9th jug.

So when the mutant zombie bikers are breaking down the door at 2AM, aim for the Minute-Made jug. The problem with this experiment is that hydrostatic shock has always been discussed in the context of wounding a human (see the wiki link toward the top of this thread). While humans are mostly water, there's no single part of the human body that is just water, IE no soft tissue, divided cavities, bones, etc.

 

[usmc1371]

What about the plain old "shock" factor? Deer looks down and sees a half a lung hanging out and runs half a mile, man sees his own lung and instantly goes into "shock". What kills him first the wound or does he die from shock? I have seen first hand humans with tiny wounds go into shock and require medical help so they don't die even though the wound is not life threatening. I don't think deer go into "shock" they know they are hurt and run away, no one ever told them that a 300 win mag should kill them DRT.