So hydrostatic shock...

Hydrostatic shock is a very real thing, it is the energy transmitted to an animal through its own body fluids reacting to the impact of the bullet, primarily when the fluids cannot move out of the way fast enough. You can see it when you shoot a deer with any relatively fast-moving bullet, you will see a wave of ripples move away from the point of impact and dust, water, mud, hair fly off the animal. The most visible effect of hydrostatic shock in harvested game animals is blood-shot meat. So, yes, it exists and has a real effect on any animal when that animal is shot with a high-velocity projectile.

Having said that, the idea that the energy from the bullet hitting the animal can disrupt its neural pathways, stop its heart, drop it where it stands, or any other nonsense of the sort, is preposterous. To take it a step further, the idea that a bullet merely passing close to a game animal can kill it is akin to believing in the tooth fairy.

On the other hand, big proponents of hydrostatic shock kills were Roy Weatherby, Parker Ackley, and Charles Newton, kind of a "Who's Who" of the gun world.
 
Elmer Keith told a story of a tick bird that fell off of a buffalo he shot, dead. I don't want to call him a liar.

It's true that the term shock is improperly used. In this case it refers to a shock wave. It also refers to systemic shock, or the sort of shock yo feel when unexpectedly taking a serious injury. You also have another type of shock, the type of medical shock when extreme injuries are causing the system to die.

The Keith bullet was the first design tha added shock waves to the impact, instead of just a round ball.the flat gameplay, the sharp shoulder, both contribute to an outward push of fluid. Is that significant? I think that the damage is better attributed to the sharp flat profile cutting a better hole.

There is no "shock," like a lightning bolt, that sends a killing burst of energy to the brain and drops the beast instantly. Sure, it happens.It is not normal.it's luck if that's what you want to call it.
 
I vaguely recall a report from Sweden that the minimum velocity for shock or "pulsatile cavern" effect was 2650 fps. Hmm, about like a 6.5x55.
 
Jim the link I posted also cites that exact velocity. It seems opinions vary or at the very least it is situationally dependent on a plethora of variables as far as if it aids in a quick kill or just some extra trimming of harvested game.
 
Having read all of the responses in this thread, and having actual expertise in the field, Scorch's post is the most accurate for the application to the average hunter.

MUCH has been learned since Fackler last wrote about the phenomenon. Being the first expert in the country to prove entrance velocity based on virtual autopsy, I had to do a lot of work in the area before a judge would let me talk about it. There are still several unknowns related to the actual effect and it certainly varies in each specific case. Reliance upon hydrostatic wave propagation as a method to kill game animals is a fools errand though.

But the answer the OPs question, frontal area of the projectile IN the animal being shot is part of the equation. A minimum impact velocity of 2200 fps has been cited by some experts, but I believe there is a range as well as a distance from the CNS and heart that is also a part of the equation. What becomes difficult is separating mechanical trauma from a bullet from a (less specific) CNS or heart disruption from a shock wave.

Several years ago I worked tangentially on a DARPA project that used stand off wave propagation to neutralize living things. It was pretty effective on small targets, less so on large targets. In any event, some of the shock wave propagation theories were validated. I have no idea where that system is today since it was generally deemed "inhumane" for the battle field.

The frequency of a wave propagating (and attenuating) through a living thing and at the point (for the heart) in the cycle it first encounters an organ which it may disrupt is part of the equation as well. A few milliseconds earlier or later and the disruption may be negligible as opposed to disrupting the electrical cycle. The electrical system in the heart is an amazing thing. There have been cases of living things being shot and the bleeding was minimal and upon post mortem examination, the heart is full of blood as is most of the body...implying the heart stopped pumping at the time of bullet impact. In similar impacts, it was clear that the subject bled out...meaning the heart was pumping.

I hope that this discussion helps explain why there is a lot of misinformation on the topic and actual observations that seem to suggest it is real, and it is false. I fully believe it is real, but I also fully believe that it is unreliable and a bit of a gamble as to whether or not it will have any influence in a specific instance.
 
From common cartridges such as the 7mm Rem Mag,30-06,etc,expanding bullets,I've seen horrendous wound channels.
When EVERYTHING in the chest cavity is soup,and about 70% of the bullet is recovered...What else is going on?
Even my little 257 AI makes football size cavities of destruction.
I got away from the 7mm Rem because I hate trimming bloodshot meat.
I've seen chest/shoulder shots make chocolate pudding clot up in the backstraps of a pronghorn.

The skin of a plastic jug is a lot tougher than mortal tissue,short of some bone and sinew.

What happens to a water jug hit with a 270/30-06/7mm Rem? It gets destroyed.
Internal high velocity water hammer. The kind of hard water you feel when you jump in the water with a belly flop.Pressure washers and water jet cutters CUT. That bullet does to the water what a pool cue ball does to the racked balls in a break.

I've seen prairie dogs do about the same as a grapefruit would.Bits and chunks hanging on the sage.
And no,it does not go that way with a 77 gr BTHP that passes through like an icepick.

If you shoot an arrow into a pond,no big deal.A big rock makes a ker-ploosh and a splash.

The water has to get accelerated .

I can't say for sure,but IMO,you get SOME at about 2000 fps,enough to matter 2400 fps plus,but that is tempered by a LOT of variables.

That RPM thing,I've thought about.180,000 or 200,000 RPM seems like it ought to be a buzz saw....but,really,I don't think so.Think of the twist rate. One in 10 inches? Well,thats one twist of the bullet as it goes through the lungs.I know it more complex,but that's a perspective on it.
 
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All the quasi-scientific information suggested here does not put pork on the table. I would be more interested in hearing about the details of actual kills, what worked for them. My biggest boar (350#) went down with a single 300 Blackout 125 gr TNT. He was facing and angled to the left a bit, I shot inboard of the left shoulder and obviously took out most of the vitals. I had not the least concern for " hydrostatic shock" etc, I just wanted an animal on the ground.

Others use neck or shoulder shots for impressive results so I read about the successful kills and their results more than the "calculator and what if crew".
 
Don't dismiss science, that's one of the things that's wrong with the world today. Nobody seems to give a damn about what it, and learning what it can tell.

Science can't possibly set up hard truths about killing animals, that's an impossible task.

For the most part, what kills an animal is just loss of blood, or destruction of body tissues. however that kill takes place is nearly irrelevant. a spear, a bullet, a rock to the head, every one of them can cause sufficient damage to kill on the spot.

You can't just dismiss all events based on a few events, that's a great scientific fallacy. and seriously, does that series of kills prove anything about anything?

in fact, use of the tnt bullet supports everything that was said about hydrostatic shock causing extreme damage and death.
 
True Brian.

The "calculator and what if crew" have provided the vast majority of the improvements in the bullets, propellants, and firearms over the past 30 years. Same types of folks who ushered in the technological revolution in the 60s and 70s and the industrial revolution in the early 1900s. None of it just happened. :)
 
I'm not pretending I have enough technical knowledge to use physics and math and define what happens.

If you get an essentially non-elastic steel one gallon can with a lid...

Like a denatured alchohol can,or a Coleman Fuel can..
Fill it with water,put the cap on.

Shoot it with a hi-vel rifle,preferably a blunt or loose expanding bullet.

If there was no significant hydrostatic shock,there should be an entrance and exit hole of approximately the bullet diameter.

What you will see is steel ripped to shreds.

Try it with a grapefruit. You will see a ball of mist.

Its not about the bullet cutting the steel or the grapefruit. Its about accelerated water doing violence.

YES,the bullet itself DOES tear flesh and fragment bones,etc.

But there is another force at work.
Call it what you want,believe it or not.Makes no difference to me. I've seen the effects.
 
mark, it's also pretty interesting that up to the the twenties, maybe somewhere around there, it was all pretty much mechanical improvements. we were still using this and that, barely understood the the double base powders, couldn't use good primers, small chemistry changes and changes in precision were still beyond us, but the greatest inventions in the history of guns were designed. The 1911 and recoil operated systems, the garand and gas op systems, bottlenecked high velocity rounds, and the first few expanding high velocity rounds.

Great mechanical strides, as far as inventions, and for the most part, what we have done since then was was slow, but steady refinements. Good lord, the way we have gone since harry pope was shooting. I read about the "hoxie water bullet" years ago, it seemed that it was a hollow point, filled with water, and a ball bearing was clamped tightly into the nose. the bearing blew the water out as well as opening up the point.

Good lord, the advancements in optics over the past sixty years is amazing.
 
I once taped a Capri sun to a piece of 3/4" plywood and shot it with a .223 35gr varmint bomb. It made a 2.5"-3" hole in the board.
If an aluminum can is placed on top of a water jug and you hit the water just right with a varmint bullet, it will accordion the can.
 
HiBC,
Try shooting the same bullet into an inner tube that is just full (no Pressure) with water. You will get a closer approximation of what happens in a body. The entire body is encased in a tough flexible container of skin. Each organ has its own skin and even at the cellular level each cell has a skin.

I have killed a number of animals and I have fired bullets into a lot of other stuff. There is nothing that responds to a bullet in the various ways that living tissue does. Two shots into similar sized animals impacting at nearly the same spot can show very different terminal ballistics. I've seen my share of blood shot meat and a few bullets that went straight through never hitting a single bone where the heart and lungs were penetrated without any sign of blood shot meat. I am by no means an expert but Dr. Fackler was an expert who actually studied gunshot wounds in people and animals. We would all be better hunters if we understood terminal ballistics half as well as Dr. Fackler. Fortunately there is an abundance of his work published for us to use. Knowledge is power, fuel up! :)
 
Dr. Fackler's study seems to me to be based on military wounds and expanding bullets typical of hunting bullets were prohibited by the Hague Convention.
 
Fackler does have some really good stuff, I use many of his papers as reference and support in my work. He wrote about 300 articles/papers. However, most of his work was in old cup and core bullets and some is not applicable to the better bullets we have today. Using some of his test methods illustrates that his approximations of living things was good, but also that a few of his conclusions are not valid for today's bullets. I use a Fackler box with glycerin and newsprint more than I use ballistic gel. So far, it is the best approximation to measure performance without shooting living things. Water is not a good approximation, and Fackler said so and was instrumental in getting the 10% ballistic gelatin as a test standard.
 
I know little about hydrostatic shock, and don't really enjoy dissecting the minute details of this sort of stuff. I can relate somewhat to shock, just by way of hunting a lot. The hog below was shot by me last night, and was shot straight up the snout...breaking both jaws and there was enough energy there to make one eyeball pop right out of it's skull. I was using my 6.5 Creedmore and I would definitely say there was some type of shock inside it's skull !
 
IMHO, hydrostatic shock does happen at higher velocities and more so with expanding bullets. Expanding bullets not only make a bigger hole, but disperse their energy while expanding and that energy is dispersed into the tissue. If one butchers their own game, hydrostatic shock is readily apparent anytime bone, and/or heavy muscle is hit. It can make a real mess of the tissue surrounding the wound channel and sometimes damage is massive. But it's something that IMHO, cannot be counted on to increase the odds of a killing shot when the hit is marginal or bad to start with. While it makes a mess of tissue and can lead to more blood loss, most of the time the damage is done to heavy muscle and not vitals. There are times when I have double lunged a deer with a good 180 gr JSP outta my old ought-six and the lungs were nuttin' but mush. Still those deer ran just as far or farther than those deer I double lunged with a bow and only had a clean X cut thru both lobes. It does tho, generally increase the amount of blood lost outside the body and thus make bloodtrailing easier, and in doing so may make recovery of marginally hit deer a higher probability.
 
I've been hunting North American big game animals for 45 years and have taken them with a variety of cartridges. The fastest "drop in their tracks" shot was a pronghorn antelope taken with a .243 rifle shooting the 95 grain SST bullet. Distance was approx 275 yards.

My cousin hunts legally in South Dakota with a 22-250 shooting 60 grain Nosler Partition bullets. He always drops 'em where they stand. On the other end of this spectrum, I've toppled a number of whitetails using my 44 MAG carbine and 240 grain Hornady XTP bullets. This is a very lethal bullet but the animal typically bounds away at the shot only to topple in mid-stride after just a couple jumps. I've witnessed this same lethality with 30-30 and 35 Remington rifles as well.

Hit 'em right with a good expanding bullet that holds together and you'll have meat on the table. Bore size is less an influence upon lethality than many hunters can comprehend.

Jack
 
It's really kind of simple, shoot the things, they bleed, they die, end of the story, really. make them bleed to death, break them down, blow out the nervous system. whether it's an arrow, a club to the head, spear, knife, sometimes one thing or another is more effective. Sometimes it puts them down quicker with a change in weapons.

Have any you ever wondered why 3 pound prairie dogs just explode if they are hit with a 22-250? Because it is hit with an enormous, hyper velocity bullet.

What would happen if you nailed a 300 pound elk with a lightly build and fragile bullet moving at 4,000 feet per second, but using a bullet that weighed almost 13 oumces, nearly 3/4 of a pound? That's eight times the weight of a 50 bmg.

what would a rifle bullet that weighs darned near a pound, fired at 4,000 fps, that is built like a V max or similar varmint bullet do to an elk? whatever area that is actually hit by the bullet is going to turn into a spray.

Seriously, this hypothetical round, 13 ounces at 4,000 fps can be compared to the vulcan cannon. the difference is that the vulcan fires a much smaller3.6 ounce projectile at only 3,500 feet or so. these things can bring down a plane or cruise missile, or sink a boat. We smack prairied dogs with things equal to that.

we could push the limits of velocity and weight to the point that hydrostatic shock would gut an animal from butt to snout. we can also kill them just as dead with a .600 ne that just blows a smaller hole from gut to snout.
 
I think there may be an overlap of ideas.
When folks are discussing the 9mm vs 45 vs 40,etc handgun debate,the temporary cavitation is not extreme or violent enough to exceed the elasticity of tissue.Its not a significant trauma or disabling factor at handgun velocities.
Agreed.
IMO,it is NOT accurate to carry that over to high velocity rifle rounds.

I also agree,each shot is different. Exactly what will happen is not real predictable.

Shot placement is the greatest factor.From a Muzzle Loader round ball to over mach 3.
 
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