Hydrostatic shock does not help kill animals

[AckleyHunter]

The guys at Barnes say hydrostatic shock isn't important. Only permanent wound cavities contribute to killing. What say you?

 

[grand veneur]

A decades-long, controversial discussion.

The so-called "hydrostatic shock" has always been a rather vague concept. Various experimental forensic studies have repeatedly shown that the cavitation with the size of the temporary cavity and subsequently that of the permanent cavity are, because of a great tissue damage, the causes of a rapid lethal effect. It cannot be ruled out that the high pressure temporarily generated during the cavitation causes damage at a distance as well, but these are collateral effects.

 

[Tex .416]

The guys at Barnes say hydrostatic shock isn't important. Only permanent wound cavities contribute to killing. What say you?

This debate goes back a hundred years or more.

Whatever and why ever, Barnes TTSX are my go to first choice for hunting for the last fifteen years. Put them in high shoulder, brain, or heart, and they deliver.

 

[375Fox]

I didn’t listen. I’ve heard lots of dumb theories before. A very accessible test to most of us is a 223 with FMJs and a 22lr with non-expanding target bullets. Hydrostatic shock, energy, whatever you’d like to call it does help speed up the kill. Take that 22 and 223 and shoot a groundhog, raccoon, coyote, any medium size varmint and compare the result.

 

[Kootenay Hunter]

I think there needs to be a bit of a clarification between hydrostatic shock and hydraulic shock. Hydrostatic is a term thrown around in hunting circles a lot, but I think a better term is hydraulic shock. That is the shock wave that moves through liquids. So no matter what peoples opinions are, hydraulic shock happens when a high speed projectile meets a liquid. And mammals are 70% water, so this applies to us.
I read an interesting paper on this a while back, that came from (I think FBI data?) that talked about the difference in the reaction to tissue against the velocity of the shock wave, and the relation to that shock wave speed to the bullet that caused it. The long and the short of the data is that they concluded (this was against impacts on humans) that the binding that occurs between cells is broken by shock waves that occur from bullets that impact above 2300 fps.
What that means is: If the bullet hits you below 2300 fps, your wound will be defined by the permanent wound channel. If the bullet hits above 2300, there will be a larger area around the permanent wound where the cells and organ structure will be inoperable, if that is the right word. Those of us that have hunted with 270/7mm rem mag/300 win mag, and had to take a close range shot, have no doubt encountered the blood shot jellied meat and organs this causes.

I tend to agree with their assessment, and think that most mammals are probably around that 2300 fps mark as well. I think this is one of the reasons why buff and larger animals tend to run a bit, and that is because we are shooting them with slower moving heavy projectiles; we sacrifice velocity to get penetration, and so they only ever have a permanent wound, vice an area that has turned to jelly. I also think this is why things like the 270 win tend to flatten deer, the impact velocities are above this threshold, and so there is a much larger are a damaged. I used to hunt with 130gr bullets, and sometimes you would pour the lungs out of the chest cavity. I think it would be hard for barns to convince me that turning the lungs to liquid happened based on the bullets path alone.

So I don't think barns is right, but they are not totally wrong either. Like all things in physics, it is a little more complicated that yes or no. And I think far too often, none of us are examining the effect of freshly shot game, having used a laser range finder and ballistic apps to note the predicted impact velocity.

 

[Whelen]

From a trauma medicine perspective, I think Barnes is oversimplifying this.


I agree that the permanent wound channel is the primary mechanism by which bullets produce lethal injuries because it consists of tissue that has been directly destroyed by the bullet. However, I don’t think temporary cavitation and associated pressure effects should be dismissed as irrelevant.


Traumatic death ultimately occurs from either direct injury to the central nervous system or loss of oxygen delivery to the brain through massive hemorrhage, airway compromise, respiratory failure, or circulatory collapse. The permanent wound channel is the primary source of that injury, but it is not necessarily the only tissue damaged. Temporary cavitation and associated pressure effects can contribute additional tissue injury beyond the bullet’s direct path, particularly in the lungs and, under some circumstances, the central nervous system. That additional injury may worsen hemorrhage or organ dysfunction, even if the bullet doesn’t directly transect the heart or a major vessel.


Like an arrow, a smaller projectile that penetrates the vital anatomy can absolutely produce an ethical kill. However, assuming comparable penetration and bullet performance, a larger permanent wound channel—and, when present, greater secondary tissue injury—will generally produce more rapid physiologic collapse.


Shot placement remains the most important factor, but it isn’t the only factor that influences how quickly an animal becomes incapacitated.

 

[Excessexpress]

It's a bit like “how does a plane fly?”

There are two main theories, the top surface creates a reduction in pressure, or the bottom surface creates an increase in pressure. The truth is, both contribute.

Unless it flies mosty through overwhelming thrust.

And so it is with bullets.

 

[Mark458]

I think hydrostatic shock definitely contributes in the harvesting of an animal. Especially in cats. Kevin Robertson is a firm believer that cats can be killed by hydrostatic shock. They are just wired different, not as difficult to flip their switch off.

I don't think you're going to kill a cape buffalo with hydrostatic shock, but transferring all that energy from a big bore caliber has a tremendous affect on their organs and tissue even if not directly contacted by the bullet. This is where I definitely feel bigger caliber is better given all other factors are equal. From personal experience I have seen the difference between a buffalo's reaction to a 375 compared to a 458 Lott. The Lott just rocks them so much harder. A huge difference in the amount of energy transferred.

A good wound channel through the vitals is an automatic kill, but shock plays some roll in the equation.

My 2 cents.

 

[Mizzou100]

Well opinions are like aholes, but for what its worth. I get quicker kills with larger slower velocity projectiles, than high velocity. Consistently my experience.

 

[AckleyHunter]

bullets that impact above 2300 fps.
What that means is: If the bullet hits you below 2300 fps, your wound will be defined by the permanent wound channel

Handgun velocities are slow, but they kill quite well. There is a video of a guy killing a cape buffalo with a 10mm handgun. It died pretty fast. In that case seems only the permanent wound cavity mattered.

If shock matters, smaller faster bullets would make bigger wounds (big bullets going really fast too, but nobody wants to lug a 50 bmg around). Also, non expanding bullets like FMJ and solids would be just as effective as expanding bullets as shock is due to velocity.

This would upend the arguement that bigger is better, because bigger usually means slower. A 9.3x62 is going to impact slower than 2300, while a 22 creedmoor will be way over that past 400 yards. If shock contributes greatly to wounding, the advantage would go to the creedmoor.

If shock matters or not, you can't argue against the permanent wound cavity's killing/bleeding prowess. And that is determined by bullet construction and impact velocity. Picking a bullet and impact velocity that gives you the biggest wound in the animal you are hunting, without excessive meat damage, is the best practice in my opinion.

 

[AckleyHunter]

Well opinions are like aholes, but for what its worth. I get quicker kills with larger slower velocity projectiles, than high velocity. Consistently my experience.

I have come to the conclusion anything can work, and work well. The most important thing is the bullet goes through the lungs. Subsonic expanding copper bullets kill way faster and pass through animals more often than would be expected.

Animals are not the indomitable monsters we make them out to be.

 

[Mark458]

Handgun velocities are slow, but they kill quite well. There is a video of a guy killing a cape buffalo with a 10mm handgun. It died pretty fast. In that case seems only the permanent wound cavity mattered.

If shock matters, smaller faster bullets would make bigger wounds (big bullets going really fast too, but nobody wants to lug a 50 bmg around). Also, non expanding bullets like FMJ and solids would be just as effective as expanding bullets as shock is due to velocity.

This would upend the arguement that bigger is better, because bigger usually means slower. A 9.3x62 is going to impact slower than 2300, while a 22 creedmoor will be way over that past 400 yards. If shock contributes greatly to wounding, the advantage would go to the creedmoor.

If shock matters or not, you can't argue against the permanent wound cavity's killing/bleeding prowess. And that is determined by bullet construction and impact velocity. Picking a bullet and impact velocity that gives you the biggest wound in the animal you are hunting, without excessive meat damage, is the best practice in my opinion.

I disagree with your assessment that shock is due to velocity. Shock is due more to energy transferred. A well constructed solid that doesn't deform at all can zip through a large animal with much less energy transferred than an expanding bullet no matter how fast it's moving.

 

[Betterinthebush]

Leopards seem have a differing opinion than Barnes (and I’m a lover of all things Barnes). Hydrostatic shock has, absolutely, a violent negative affect on an animal’s critical systems.

 

[Hififile324]

Hydrostatic shock can and does cause wounding and death. I was sent to a 3 week school for Homicide Investigators taught by Dr. Vincent DiMiao. During our instruction on gunshot wounds and their mechanics he provided us videos of his experiments on Cadavers and some live animals getting shot. The lessons learned was Hydrostatic shock is a wounding mechanism.

Hight Velocity 2,000 - 3,000fps causes shock waves that causes cavitation. During this tissues tear and bleed, vessels tear and bleed. One example was a bullet hole from a rifle that missed the heart and aorta by inches. But the shock wave jerked the aorta out of the heart.

We as a collective group of hunters demand penetration so we can destroy a vital organ for quick death. Sometimes we need a big bullet at moderate velocity to get there. If it is accompanied by massive hydrostatic shock that furthers the goal. You need velocity to increase hydrostatic shock.

Roy Weatherby wasn't too far off in the 1940's!

 

[BryceM]

A sharp blow to the central nervous system (either brain or spinal cord) immediately incapacitates an animal. This doesn't need to be a direct hit to the cord or brain either. If you want to call the impact "hydrostatic shock" that's probably reasonable.

While it's "knocked out" it often bleeds out, or dies of hypoxia due to a pneumothorax.

 

[Grumpy gumpy]

Didn’t the us army do a heap of trials shooting goats to study the effects of wound injuries and traumatic (fatal) injuries. I had the paper on the results but lost it when my iPad died, before I could read it.
Gumpy

 

[Betterinthebush]

A sharp blow to the central nervous system (either brain or spinal cord) immediately incapacitates an animal. This doesn't need to be a direct hit to the cord or brain either. If you want to call the impact "hydrostatic shock" that's probably reasonable.

While it's "knocked out" it often bleeds out, or dies of hypoxia due to a pneumothorax.

Perfect explanation

 

[Miletic]

Hydro shock plays an important role in killing an animal or anything alive. The tissue is destroyed tremendously under the pressure caused by the speed of the projectile

15 cm away from the point of impact, destroyed tissue

 

[AckleyHunter]

I disagree with your assessment that shock is due to velocity. Shock is due more to energy transferred. A well constructed solid that doesn't deform at all can zip through a large animal with much less energy transferred than an expanding bullet no matter how fast it's moving.

So in your opinion, limited expansion bullets like copper and bonded bullets won't transfer as much energy as fragmenting bullets and are worse at wounding?

Also, according to @375Fox analogy, speed is the only difference between 22lr and 223 using nonexpanding bullets. One has more 'shock' then the other without expanding.

 

[AckleyHunter]

Hydro shock plays an important role in killing an animal or anything alive. The tissue is destroyed tremendously under the pressure caused by the speed of the projectileView attachment 779455
15 cm away from the point of impact, destroyed tissue

So in your opinion, smaller, faster bullets make bigger wounds, and presumably kill faster?