Large caliber magnum rounds and hydrostatic shock

GooseGestapo said:

One thing I haven’t seen considered is the secondary projectile effect of hitting bone. Early previous poster came close when describing what he called a “porcelain china” effect.

A bullet hitting bone causes secondary projectiles to impart additional damage, often far greater than that simply imparted by the primary projectile itself. If you’ve ever seen a ~200lb deer hit in the neck by a 140gr bullet from a 7mmMag at ~3,000fps to the spine can envision what I’m describing. The exit wound will be several inches in diameter. It’s not cavitation in this instance. Cavitation is simply the mechanical “boiling” of a fluid by energy transmitted by an object. Like the bubbles in the water from the passage of a boat propellor. Shock wave damage is like the boat wake, but tissue being elastic can absorb it somewhat (temporary wound cavity). It’s the dozens of bone shards like tiny razor blades shredding tissue as it passes. ie: shrapnel.

Hence, a large meplat will displace more media than a small meplat. Simple physics. Higher velocity creates greater inertia, a different expression of energy than kinetic energy. Both factor into terminal performance.

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Good synopsis.

Hydrostatic Shock is a controversial subject, not just among hunters, but also among scientists and surgeons. Not only that it exists, but how much it contributes to incapacitation. While I believe it does exist to some extent, I also believe it is not a real contribution to the incapacitation of animals at revolver velocities. Just MTCs from my experience.

Tradmark said:

Once again, any wound larger than the caliber of the bullet is due to hydrostatic shock. End of story. If you didnt see it i suggest you use better bullets.

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I have processed/butchered more deer than I can remember in the last half a century. This includes animals shot with bow, handguns and rifles. I have seen wounds larger than projectile diameter in all of them. Angle of the shot, along with what was hit along the path of the projectile(before and after entering the body) and with high enough velocity, Hydrostatic shock, all contributed. I have seen bone shattered and bleeding/bruising far away from the wound channel, even with bow velocity projectiles. This is surely not from Hydrostatic shock, but direct pressure from the projectile. I have seen what a ought-six does to soft tissue when hit at close range and will readily admit that some of it was probably due to Hydrostatic shock. I have also seem wound channels produced by 30-30 and .32 Special, that were a clean hole all the way thru, even after hitting shoulder bone. These were probably shot at a distance where the velocity had fallen off enough that Hydrostatic shock was not any contribution. As a kid, many of the older hunters I knew, went to faster calibers than their old vulnerable 30-30s just because of this.

My bullets are just fine. They do exactly what I want them to do when I do my part. I do not have to have wound channel measures in multiples of inches in order to consider it a clean and humane kill. I gave up hunting deer with rifle calibers more than a dozen years ago. I don't concern myself with Hydrostatic shock any more as I truly believe I don't have the velocities to achieve it to any great proportion. This even with the .460 in a long piped revolver, or .357 and .44 mag in carbines. While I have had bullet fragmentation with my carbines and have since changed bullet types and construction because of it, I changed to something that would give me better penetration at those higher velocities, even tho the wound channel itself may be not as ugly.

We as hunters, should use what we are most confident with and what has worked best for us, in our hunting scenarios over the years. We may not agree with others on everything, but what we need to agree with, is that condescending and attempting to belittle others for what they believe works the best for them, is not doing anything to help promote the sport of hunting. Again.....JMTCs.

Dr Gary Robert's has stated that they start seeing temporary cavitation as a wounding mechanism with heavy hot loaded 44 magnum. So while 2000 FPS is a good generality for temporary cavitation wounding, it's not a set on stone thing.

Testing done by, I believe Dr Fackler, showed BBs about at 4000+ FPS showing no temporary cavitation wounding in ballistics gel. Bullet shape also plays a good role as well.

buck460XVR said:

We as hunters, should use what we are most confident with and what has worked best for us, in our hunting scenarios over the years. We may not agree with others on everything, but what we need to agree with, is that condescending and attempting to belittle others for what they believe works the best for them, is not doing anything to help promote the sport of hunting. Again.....JMTCs.

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Who is belittling who? I'm not seeing it. tradmark kills more animals with handguns regularly in a year than anyone I know (it pisses me off - LOL!), and he is meticulous about necropsies and cataloguing bullet performance. I don't see any condescension in his responses here. I have dug through numerous gut piles with him during our Bovine Bash so that we can get a clear picture what our bullets and loads are doing on real flesh. I think we all need to discuss without taking things personally, but what do I know...

I think that the rather arbitrary 2,000 fps threshold is a load of bovine fecal matter and I have seen evidence of hydrostatic shock (or hydraulic pressure, or voodoo magic, or whatever you want to call it) at lower velocities. If there is bleeding and bruising far away from the projectile I would argue that's a clear cut case of hydrostatic shock in action. Of course the nose profile helps dictate the wound channel size, but speed ups the ante considerably.

There is so much questionable "conventional wisdom" that gets repeated in perpetuity that it's hard killing this so-called wisdom resetting the thought process. I challenge it at every opportunity, but it's exhausting.

If my responses in these discussions seem incomplete or short, it's just that I am a bit fatigued discussing topics like these on the internet. My apologies, but I'm a tad burned out.

Yeah no condescension implied. Its just that hydrostatic shock is very very misunderstood. Its not just the roy weatherby idea if you shoot high velocities into an animals foot itll transmit shock into the chest and kill the animal. That is not true. Now theres ample pics if an animal losing an entire lobe of the lung when shot with high velocity, by pistol standards. This is hydrostatic shock. My cousin just shot an axis doe this weekend at my ranch. Texas heart shot. Exited the right front shoulder and in just right of center in the back ham. Ribs on both sides were broken. Thats hydrostatic shock. It was well below 2000 fps.

Some will say that wont happen on a large animal and they would be correct as it was a small doe but it speaks to what is happening in the animals.

Another thing to consider is the 2000 FPS threshold (again, not set in stone) is based on human flesh. Animal tissue is a different animal..... get it! Haha

It also matters on the bullet and type.

MaxP said:

If my responses in these discussions seem incomplete or short, it's just that I am a bit fatigued discussing topics like these on the internet. My apologies, but I'm a tad burned out.

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Same here. My responses have been from experience and my personal opinion. Unlike others, I'm not sating it as fact or presenting it in any other way. As I have said before, the whole idea behind Hydrostatic Shock and it's ability to incapacitate is theoretical, argumentative and controversial, even between scientists and surgeons. It's no wonder those of us that are just hunters can't agree. As I said before, I'm not saying that Hydrostatic Shock does not exist, my opinion is it is a moot point when it comes to deer being shot at revolver velocities. been that since the start. Some folks claim that Hydrostatic Shock starts at velocities as low as 1100 FPS. I'd guess it starts lower than that, just that it doesn't exhibit any signs. Even at the velocities when it is readily apparent, does it really incapacitate? Does that 4000FPS projectile hitting the rear leg really stop the heart? That is what the premise of Hydrostic shock is about....remote neural damage, not the shattering of the leg bone all the way to the pelvis. As for the larger meplat bullets creating more damage, in my opinion, one reason it is because they tear thru soft tissue taking more tissue with them as they go. While folks claim a Wadcutter "cuts" thru it's paper target, it actually is tearing. Just that the paper fibers are short and tear clean, where as the pointed tip bullet just pushes those fibers away. Same with soft tissue. It's elastic and with stretch with the passage of a projectile. The wider the meplat, the more tissue it grabs and stretches before that tissue fiber breaks, the larger the hole. This is why there can be bruising(tissue bleeding) far from the wound, not from shock waves. but because the tissue was stretched before it broke.

Again, JMTCs.

MTMilitiaman said:

Hydrostatic shock refers to the pressurized shock wave that travels away from the projectile when it encounters a liquid or semi-liquid solid. While these forces exist at lower velocity impacts, most living tissue is elastic and fairly resistant to these forces under a certain projectile impact velocity. Tissue will be displaced but will stretch and rebound with little or no damage. However, above about 2000 to 2200 fps, we see that these hydrostatic shock forces become too fast and too violent for elasticity of the tissue.

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This is not hydrostatic shock, by hydraulic shock. The terms are not interchangeable.
Hydraulic shock is the civil engineers term also known as water hammer but in terminal ballistics context refers to the pressure of accelerated fluid particles that create the temporary wound channel.

Hydrostatic shock transfer refers to the effect when shock waves travel through flesh to distant nerve centers, disrupting their ability to emit electrical impulses.
https://www.ballisticstudies.com/Knowledgebase/Effective+Game+Killing.html

It may not be correct but in trauma circles they use the terms interchangeably and no one cares about the differences and the terms are largely interchangeable bc everyone knows what every means.

I get the point of tearing fibers, but when you take the same bullet and run it faster the bruising happens further and further away. Same diameter, so i theres hydrostatic/hydraulic shock, whats the higher velocity doing? And whats doing it?

Tradmark said:

It may not be correct but in trauma circles they use the terms interchangeably and no one cares about the differences and the terms are largely interchangeable bc everyone knows what every means.

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Yeah.....but, the same could be used for the words Clip/Mag, and we know where that goes. For me the main difference in mindset is the instant incapacitation to primary organs and the CNS that is the theory behind Hydrostatic shock, as opposed to Hydraulic shock that may help incapacitate an animal over a period of time because of more blood loss.

Tradmark said:

I get the point of tearing fibers, but when you take the same bullet and run it faster the bruising happens further and further away. Same diameter, so i theres hydrostatic/hydraulic shock, whats the higher velocity doing? And whats doing it?

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I believe it has to do with the elasticity of soft tissue itself. Higher velocity projectiles stretch those tissues farther and with more force before the tissue tears, thus making the tear itself larger and more irregular. Slower projectiles allow the tissue to move away and around instead of pushing them forward. Same is goes for flat nosed bullets with wide meplats as opposed to spire point and round nosed. Same with expanding bullets as opposed to non-expanding. Bruising is not a form of injury, but a result of bleeding from an injury. It's blood that collects under the skin and within soft tissue from bleeding elsewhere. If it wasn't, how could we reduce bruising and swelling to ourselves by applying ice to the injury. Blood meat around the wound channel is basically this.....just blood from the primary injury collecting and coagulating in the tissue surround the injury. Sometimes when I skin an animal(especially in a boiler room shot), the blood meat surrounding the exit would is massive and makes the wound itself look much larger than it is. Once removed tho, the wound is not nearly as wicked looking. One reason I skin my deer as soon as possible and remove blood meat and coagulated blood from around the wound, is so that the blood does not continue to move into the surrounding soft tissue and taint more meat.

But again, this is me. YEMV.

Always good to get on the same page terminology wise so it doesnt go 17 pages with people talking past each other

It's kind of funny how we hunters dissect subjects like this. When I was a young man I studied sectional densities, ballistic coefficients, energy figures...I sectioned bullets to look at their jacket design, dug bullets out of game and weighed and studied them. Don't get me wrong, even now when I gut any animal, I always trace the path of the bullet and hope to recover bullets. But as I've gotten longer in the tooth, I've realized that all we need do is select a bullet heavy enough and just fast enough to make its way through both lungs, and the animal will expire shortly. Where deer-size are concerned I've lung shot them with calibers as small as a .222 Remington and 50 gr. factory SP's up to .375 Winchester and .44 and .45 caliber revolvers. They all died because I didn't ask of the bullets more than that of which they were capable.

So, we can argue hydrostatic, hydraulic, hygroscopic, monosodium disulphide, and how much larger a wound channel may or may not be at 1000 fps vs. 1900 fps. Bottom line, at least in my world, is just poke 'em through lungs with something reasonable, they'll assume ambient temperature soon enough.

35W

It’s fluid dynamics . I’m sure the correlation is similar to doing a belly flop into the pool rather than a pencil dive.

The belly flop disturbs the surface of the water much more violently than the pencil dive because of the ‘profile’ your body impacts the water and displaces it more rapidly.

35 Whelen said:

It's kind of funny how we hunters dissect subjects like this. When I was a young man I studied sectional densities, ballistic coefficients, energy figures...I sectioned bullets to look at their jacket design, dug bullets out of game and weighed and studied them. Don't get me wrong, even now when I gut any animal, I always trace the path of the bullet and hope to recover bullets. But as I've gotten longer in the tooth, I've realized that all we need do is select a bullet heavy enough and just fast enough to make its way through both lungs, and the animal will expire shortly. Where deer-size are concerned I've lung shot them with calibers as small as a .222 Remington and 50 gr. factory SP's up to .375 Winchester and .44 and .45 caliber revolvers. They all died because I didn't ask of the bullets more than that of which they were capable.

So, we can argue hydrostatic, hydraulic, hygroscopic, monosodium disulphide, and how much larger a wound channel may or may not be at 1000 fps vs. 1900 fps. Bottom line, at least in my world, is just poke 'em through lungs with something reasonable, they'll assume ambient temperature soon enough.

35W

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Depends on what you are hunting and how much damage it can inflict just being poked through the lungs. Also, some animals head places where recovery can be horribly difficult if allowed to run off and expire. While I agree in most instances that’s good enough, some of the animals I’ve hunted need to be put down more decisively.

MaxP said:

Depends on what you are hunting and how much damage it can inflict just being poked through the lungs. Also, some animals head places where recovery can be horribly difficult if allowed to run off and expire. While I agree in most instances that’s good enough, some of the animals I’ve hunted need to be put down more decisively.

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Oh I agree completely Mr. P. As the game gets larger, so should the caliber. Just musing over the excruciating minutia of this subject when a 200 lb. whitetail is the largest thing most here will ever shoot.

35W

35 Whelen said:

Oh I agree completely Mr. P. As the game gets larger, so should the caliber. Just musing over the excruciating minutia of this subject when a 200 lb. whitetail is the largest thing most here will ever shoot.

35W

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You are so right.

VERY interesting posts here. Many are saying the same thing but with different terminology. I agree with the initial post, in that it has been my observation, from testing and actual shootings involving handguns that 'hydrostatic' shock does not occur at handgun velocities. But what some are unknowing making reference to here is the difference between 'energy' and 'momentum'! This extreme penetration of heavy low velocity bullets is due to their momentum, or the ability to 'push' through a target. Yes, bullet 'design' in non expanding bullets is a factor, but it is a secondary factor in their performance. The energy formula uses the square of the velocity and the momentum formula does not so they are 'apples and oranges', but most people in this business talk 'energy' only. Both are principals of physics we must consider in this discussion. That said a 'long (deep, hopefully through and through) wide wound channel is what matters. The rest is nice when it occurs, but don't count on it!!! The other 'myth' which I see discussed on many forums is 'energy transfer' being the 'all important' consideration in bullet performance.

The invention and use of the higher velocity Minie ball during the Civil war caused more amputations due to secondary missiles from bone fragments causing shattered bones instead of a simple pulped penetration. This has been noted in medical journals of the time.
I'm thinking the kinetic energy of the large heavy bullets is transferred into the target along hard bone. Modern bullets are generally faster and smaller and hydrostatic forces come into play.

Come on guys, energy is nothing but math and cannot be accurately correlated with how well a bullet kills. If it this were the case, then the .22 Hornet (45 gr. @ 2800) and the "standard" .44 Magnum (240 gr. @ 1180) round would be equal. T'ain't so.

35W

Love this thread, there is so much involved with so many variables that comparisons are endless with it starting with comparing the
impact with the STATIC AIR TO THE TARGET with the effect of that can be seen with air compression & displacement - in slow motion.
Also being a near victim of a 30 caliber round going by my head & feeling that displacement on its way by me, I can't imagine what
the actual impact would feel like , let alone see it done to a human.
Keep up the chatter on this. I have to go.