Hydrostatic shock, what's your opinion?

[Oliveralan]

Hello everyone,

I'm curious as to what you think about hydrostatic shock. Ive read quite a lot and it seems to be logical but yet there are studies disproving it.

Have any of you witnessed a kill you believe to be hydrostatic shock? (abdomen shot causing bangflop) or such.
I watched an episode of mythbusters where they blew open a safe by suspending a small explosive charge in the middle and filling it with water. The water then transfered the force to the door ripping it straight off. They repeated the experiment with no water in the safe and the charge did absolutely nothing. Also, the water transfered the force to the objects inside the safe, breaking them aswell.

I would think a big bullet going real fast would bring this about, anyone land a gut shot on an animal with something like a 30-378? be interesting to hear what it did.

Please post your thoughts and opinions.

Oliver

 

[MontanaRifleman]

I used to use the term hydrostatic shock until this past year when I learned in another forum in a discussion of the same topic that hydrostatic shock is a misnomer.

From Wiki, the definiton of hydrostatice...

Fluid statics (also called hydrostatics) is the science of fluids at rest, and is a sub-field within fluid mechanics. The term usually refers to the mathematical treatment of the subject. It embraces the study of the conditions under which fluids are at rest in stable equilibrium. The use of fluid to do work is called hydraulics, and the science of fluids in motion is fluid dynamics.

Note the last sentence regarding hydraulics.

Here is a definiton of static...

static (stat′ik)

adjective

1. of bodies, masses, or forces at rest or in equilibrium
2. not moving or progressing; at rest; inactive; stationary

So the more correct term is hydraulic shock.

Now that we have that out of the way, let's look at the safe experiment. What's different about a safe and animal flesh? Elasticity or the lack of it. Materials that dont bend or flex wiil break more readily tham materials that are elastic or flexible. So the safe experiment does not apply to hunting. It does show that that liquid transmits pressure better than air because it does not compress.

Animal tissue is is elastic and it will stretch and return to it's former state if it's not stretched beyond it's elastic point. This aspect of terminal balisitics is know as temporary wound channel. Most "shock energy" transmitted through an animal's body is absorbed. If there is enough hydraulic shock to exceed the the elastictic limits of the tissue then it will not return to its former state and we have permanent wound channel. More fragile tissue such as lungs and liver would be more suspetible to permanant damage then lets say the heart, flesh, etc.

Here is where a bullets design is important. The shape and velocity of the bullet as it passes through an animal will detremine how much permanant damage is done. The more flat/square the frontal area is and the faster it is moving, the more it will deystroy tissue by exceeding the tissues elastic limits. This in turn cause hemoraging, which in turn causes low blood pressure, which in turn causes a lack of oxygen to the brain, which in turn causes death. the more flat/square surfaces of monmetal bullets and blunt hard cast bullets do more damage than rounded front mushroomed jacketed bullets which do more damage than spitzer shaped non-expanding bullets. The later doing very little damage at all unless it directly strikes a critcal organ such as the heart or spine, etc.

You will often hear or read arbitrary minimum KE numbers needed to kill a particular species of animal. These minimum energy numbers have nowhere near the required energy to deystroy organs or inject any letahal hydraulic shock to the animals system. What they better represent is the "momentum" the bullet has to penetrate the animal which is based on the bullet's velocity, mass and shape. The bullets shape as it impacts and passes through is dependant on its design and construction. The more flat and greater the frontal area, the more momentum it will need to penetrate and the more permenant damage it will do. The bullet will also loose some energy when it is deformened on impact which means it will loose some velocity/momentum.

In the final analysis, hydraulic shock *usually* does not do much signifacant damage to the animal other than the permenat wound channel created by the bullet, because of the elasticity of the animals tisssue that absorbs the hydraulic shock and returns to it form. The best strategy for killing animals quickly, other than destroying the CNS, is to put a hole through it where it will loose the most blood the quickest and the larger the better. Animals are not "shocked" to death. They die as a result of lack of oxygen to the brain period. In some rare cases it might be possible for hydraulic shock to cuase the heart to fail which in turn stops oxygen to the brain. But that's all complex and difficult to quantify.

 

[ATH]

Well, an animal is different from a bag/box full of water but all of the energy that a bullet leaves inside an animal has to go somewhere; it doesn't just disappear. Anyone who has had a bullet expand well in an animal is familiar with the massive damage that occurs many inches away from where the bullet actually passed. Call it "hydristatic" shock or just energy dispersion, the name is unimportant but the energy delivered from a bullet can obviously do a lot of damage outside the actually bullet path.

Last year I shot a doe with a muzzleloader. I did not have time to range her so held high, and hit high. The bullet was a bonded Shockwave and left no sign of expansion as it passed through the very tops of the lungs and under the spine, touching nothing except the skin on both sides and the tips of both lungs. At no point did it touch the spine or any bone connected to the spine. Yet the dead dropped dead as a doornail when the bullet hit her, never even flinched. I jogged the 140 yards up to her immediately, and she was done when I got there, I never observed ANY movement and she was always in sight. Obviously the energy from that bullet passing was enough to disrupt her spine permanently, even though it passed through soft tissue 3 inches away.

 

[bigngreen]

I shot a few deer with my 22-250 with 55gr v-max bullets at around 400yrds and saw some very interesting result. All hits were ahead of the diaphragm and I found the intestines and stomach blown up and bloody, I contributed it to hydraulic action. The animals ran maybe 30yrd and then tipped over, the bullets blew up and did not actually do much direct damage but from one end to the other all the organs were torn or damage indirectly.
This year a friend shot a bull elk with a 300WBY and 165 Barnes, the hit was just above the heart and trashed the lungs but the bullets blew up not reaching the off side. The gutts in this elk were torn up, but it did not directly die from it.
In both cases the animal were feeding in alfalfa field and they where tight, not like animal shot that have been living in the mountains on grass.

 

[Oliveralan]

Bigandgreen, I have had an experience like that aswell, I shot a doe in the neck at about 80yards with a 150grain round nose bullet out of my .308win going relatively fast and the brain was shot out through the eyes, I too attribute this effect to hydraulic shock. I beieve this is also how Berger VLDs perform so well.

 

[Oliveralan]

MontanaRifleman:
I'm aware the normal way of dispatching game is to disrupt te bloodflow and oxygen supply to the brain. I'm wondering if it would be reliably faster to shoot an extremely fast bullet to cause massive shock and temporary wound channel trauma to kill the animal. Like aiming for the neck-spine junction and even if you miss a bit the shock will kill the game. Will test this shot next time I hunt deer.

 

[shooters]

A few years back, I made a somewhat bad shot on a big whitetail. 278 yards away. Shot was low and a few inches infront of the hinde quarters. Deer didn't even quiver. Hit/Drop. I saw no signs of any damage to any major arteries, vital organs, or spine. No bone either. 300 RUM 200gr. Accubond 3095fps. Don't have any real reason on how the bullet killed him expect for massive body shock???? Same thing happened this year with the wife's buck except she hit it in the lungs. Other than that, not much other damage. Hit/Drop. ????


J. Sibble

 

[Oliveralan]

same thing happened to me when i shot a 26lb raccoon in texas. hit it pretty low and it just dropped, that's when i started believing this shock theory. The spine is very fragile and i dont think damage has to be visual, enough shock to it can probably kill an animal.

Shooter:
That's the second time ive heard about mysterious kills with the 300RUM today, just have to be that big bullet going at over 3000fps displacing a lot of water in the animals body.

 

[MontanaRifleman]

MontanaRifleman:
I'm aware the normal way of dispatching game is to disrupt te bloodflow and oxygen supply to the brain. I'm wondering if it would be reliably faster to shoot an extremely fast bullet to cause massive shock and temporary wound channel trauma to kill the animal. Like aiming for the neck-spine junction and even if you miss a bit the shock will kill the game. Will test this shot next time I hunt deer.

It is interesting to read these accounts. I have shot maybe 30 deer, elk, antelope and a bighorn ram. They were all fatal first shots and the ram got 3 more insurance round through it while it stood there watching me. I have never seen any damage that was not directly caused by the bullet. I gut shot a couple of antelope just behind the diaphram and they walked about 50 yds and fell 0ver. I think I got their livers but there was no damage to their organs other than the bullet hole. I Texas heart shot a buck antelope last year with a 180 SP out of a 300 WSM and recovered the bullet under the hide of the front shoulder. The bullet lost about half its mass and there was a good deal of lung damage, which might have been caused by both shrapnel and hydraulic shock. But the intestines, stomach etc., were in tact other than the bullet hole. All my game has been taken with a 7 RM and a 300 WSM with the exception of my first deer, taken with a 243 and this years buck antelope taken with a 25-06. Oh yeah, shot one whitetail buck with a 12g slug. It needed a knife in the ribs to finish it. another doie shot with a slug expired fairly quickly.

The 7 RM and 300 WSM are high energy rounds and they caused varying amount of damage, but nothing other than direct permanant wound channel. Sometimes that permenant damage in the lungs was a little more extensive than other times.

I never had any animal fall over due to shock or at least that I'm sure I could atrribute to shock. A couple of antelope that were on the dead run piled up immediately. One shot at the base of the neck went down like a sack of potatoes. Last year two doe antelope went straight down with high lung shots just a couple inches below the spine. Most of the deer walked any where from a step or two to a few yards. And a big bull elk shot at 15 yds leaped straight up in the air, spun 180 degrees, took one leap and piled up. That was an interesting one because I was so close and the velocity of the bullet out of the muzzle of the 7 RM was high. I was literally able to see a violent shock wave go through the entire body of the elk. But it didn't immediately collapse.

Anyway, I have found the high rib shots to be very effective, sometimes dropping them imediately in their tracks , but there is always a good deal of damage with the shot. It's interesting to hear or read about animals that have been dropped and appear dead, get up after a few minutes, sometimes when you grab their horns. I think that the shock of the bullet might often cause the body to go into extreme shock and loose consciousness and then expire as it's laying there hemoraing. And I think shots in close proximity to the spine can cause a shut down to the CNS.

 

[MontanaRifleman]

A few years back, I made a somewhat bad shot on a big whitetail. 278 yards away. Shot was low and a few inches infront of the hinde quarters. Deer didn't even quiver. Hit/Drop. I saw no signs of any damage to any major arteries, vital organs, or spine. No bone either. 300 RUM 200gr. Accubond 3095fps. Don't have any real reason on how the bullet killed him expect for massive body shock???? Same thing happened this year with the wife's buck except she hit it in the lungs. Other than that, not much other damage. Hit/Drop. ????


J. Sibble

Interesting... last year I remember reading a thread and seeing the pics of an antelope that was shot through the ribs with a 300 RUM, that ran for maybe a 100 yds. It had about a 6" exit hole. It's amazing to see the diferent results from different experiences.

 

[MontanaRifleman]

Bigandgreen, I have had an experience like that aswell, I shot a doe in the neck at about 80yards with a 150grain round nose bullet out of my .308win going relatively fast and the brain was shot out through the eyes, I too attribute this effect to hydraulic shock. I beieve this is also how Berger VLDs perform so well.

If you look at a deers skull, you'll see that the brain is very well encased and is basically impossible to remove without severely fracturing the skull. I'm guessing you probably saw some flesh that surounds the eye being pushed out. In anycase it's an interesting report.

 

[Oliveralan]

If you look at a deers skull, you'll see that the brain is very well encased and is basically impossible to remove without severely fracturing the skull. I'm guessing you probably saw some flesh that surounds the eye being pushed out. In anycase it's an interesting report.

I didnt examine it too closely, but the eyes had popped out of the skull and there was mush hanging out from behind. Maybe it was or wasnt brain. I shot it near the base of the skull, maybe it had fractured, not sure.

Hmm the shockwave of a shot near the spine knocking an animal out that then expires from hemoherrage is viable. I suppose it's pretty hard to go there and find out if it died from the shock or blood loss. Does the heart keep pumping blood if the spine where somehow shutdown or the line of communitcation from the brain cut off? If not, then if there is significant bleeding the death could be attributed to hemoherrage, if there isnt then it died from the shock to the spine. But that's based on that an animal keeps pumping blood after the spine is hit by a shockwave like this (not sure if it is, just building on that).

 

[bigngreen]

I think there is a lot of game that drops to the shock of the hit, especially if you hit a heavy bone but then the actual cause of death is the damage to arteries or collapsed and shredded lungs. I think the high shoulder shot on an elk is an excellent example, shooting an elk through the shoulder will not kill them unless you trash the dorsal vein under the spine, the shock of the bullet hitting the shoulder and the shock wave under the spine drops them and people think they were dead before they hit the dirt when in fact they are knocked out and then bleed to death.
This exact thing happened to a cow elk I shot last year, I was yet again attempting the high shoulder shot and at the shot she dropped just like in the videos, her legs came up to her chest and she bounced of the ground, legs went straight out quivering. I though I had finally hit the spot, after about five minutes we ran over and wacked another cow out of the herd, so half an hour later we look over there and her head is up, so I get out there and sure enough she was still ticking so I take care of it and start checking out what happened, the shot went low and hit the heavy leg bone just in front of the heart, then the 168gr TSX turned straight forward exiting out the front of her leg, I shot her with her head down feeding and the bullet had just enough poop left to go into the neck and cut one of the main atteries. Point being, that hit was 18in from a CNS hit but it had the exact same effect and did not enter the rib cage. I got lucky and I think this is what happen in the field when super hero drops an elk but can't find it, they knock it out but don't do enough damage to the dorsal vein or the top of the lungs to kill and the animal comes to and takes of.
The way the Berger works is real good for this kind of shot as the bullet blows up and directly affects the lungs and dorsal vein more than a controlled expantion bullet, so they drop to the shock to the CNS but stay dead due to bullet fragments blowing up lungs and arteries.
The elk I shot this year with a Berger through the heart showed not evidence of hydraulic shock, the only damage to the heart and lungs where from bullet and bone fragments, there was no brusing on the lungs or tears in them, just shredded holes.
I think the best way to get it done is with a shot that directly effects the delivery of blood or oxygen to the brain, relying on the CNS being effected enough to kill the animal is not a sure enough deal unless the bullet directly interacts with the CNS, either forward spine or brain.
Wow, I kinda got carried away.

 

[Pdvdh]

Hydraulic shock or Hydrodynamic shock would probably be better descriptors.

I read an article written by Jim Carmichel (used to be - maybe still is - Gun Editor with Outdoor Life). In his article, he presented the findings of bison or cows that were culled with high powered center fire rilfes on a ranch setting. These animals were center-shot through the rib cage with broadside hits, best as I remember. A person might be able to do a Google search and find the article. These animal's reaction to the bullet were observed and recorded. After the cull, veterinarians performed pathological examinations (autopsy) of the animals. Some percentage of the animals dropped at the shot - instant lights-out deaths. Others died over variable periods of time, same as big game animals do in response to similar bullet hits. The interesting part? All of the animals that expired instantly were observed to have suffered massive strokes. Vessels and arteries ruptured in their brains, and it was more or less concluded that the hydraulic pressure peaks that were transmitted through the blood vessels and arteries overpressured and ruptured arteries/vessels in the brain. Mr. Carmichel surmised that if the timing of the bullets impact coincided with the peak animal blood pressure that the added hydraulic pressure might be enough to kill by massive stroke. While another animal stuck very similarly, but when blood pressure was at a lower level might avoid massive stroke, and not produce an instant body-slam kill.

I've hunted for a long time. Seen quite a number of large game harvested by bullet. I have no doubt that high velocity impacts (with bullets of weight reasonably proportionate to the size of the game animal) can cause immediate death. Death can be so instantaneous that I personally concluded that bullet impact caused shock must be disrupting or short circuiting the nervous system. Then I read the Carmichel article. I'm not completely sold on that explanation, but the Vets carefully autopsied all of these animals shot during this study, and massive brain strokes were observed on the ones that collapsed dead on their feet.

The most dramatic instant death from a solid body hit I ever observed was a large boar brown bear I shot from a distance of 130 yds with a 338 Imperial Magnum. I used 225 grain Trophy Bonded Bear Claw bullets, one of the Jack Carter bullets before the company was sold to Speer. A 338 Imperial Magnum is virtually identical to the 338 Edge. This bear was standing broadside. I aimed center of the ribs just behind the front shoulder muscles. He collapsed so quickly I missed most of it due to rifle recoil. The way he dropped, and without so much as a twitch on the ground, I thought I might have brained him. This bear was standing on three feet of snow pack, and he was completely visible from my position. He squared 10' 5" and I could only estimate his weight at around 1000-1100 lbs. I couldn't believe a lung shot could put down a 1000 plus pound bear - instant lights out - like that. Because of these doubts, I waited and watched for a good 15 minutes before even getting up from my shooting position. I never saw any movement. About 25 minutes after the shot I was finally standing next to him, half expecting to see a head shot bear. Upon completely skinning this bear out, I can say with confidence the bullet struck right where I'd aimed, mid-height in the ribs on a completely broadside shot. I cut into the heart lung cavity forward of the diaphram and could find no impact on the inside ribcage of the offside ribs. The bullet never made it to the far side ribs, yet the animal was dead on impact.