Velocity Effect on Wounding

Steve762us said:

Hope you're not including an M855 out of an M4, in that "most".

Click to expand...

My only source of round performance for M855 ammo round is Wikipedia, where one article shows the M855 5.56mm (5.56 × 45 mm) round as having a velocity of 922 m/s (3,025 ft/s).

A second Wikipedia article at military.wikia.org/wiki/5.56×45mm shows performance specs for three different versions of the M855. I don't know which version is most commonly used, but even the slowest of the three is only 30 fps below the 3,000 fps.

the amount of lateral force necessary to exceed the elastic limit of internal structures of the animal you are shooting. I'm guessing it involves the bullet design (mainly the ogive, and expansion qualities of the bullet used) and the amount of lateral acceleration created by that design and, therefore, by the amount of longitudinal velocity of the bullet.

there should be a velocity for each elastic limit of each internal structure. so, there should be a velocity great enough, for the bullet used, to exceed the elastic limit for enough internal structures to cause permanent lateral wounding (as opposed to just punching a one caliber hole through the animal).

figuring out what bullet design and what velocity will accomplish this will be a calculus nightmare. good thing people shoot animals and can actually see what works and what does not work.

murf

There's been at least one study I could find that indicates a "shock" can and does happen at less than 2200 FPS.

I was doing some research as to the "why" the .357MAG with 125grn has a favorable reputation as a "stopper". This sort of flies in the face of the conventional wisdom that "all service calibers perform basically the same with modern defensive ammo" mantra. There may be some physiological "stuff" to it. There's been at least 1 study that look at "hydro-static shock" that set the parameters at 500 ft pounds and 12" of penetration, which is pretty much what the .357 125 load delivers.

Energy Transfer Required for Remote Neural Effects Our own research (Courtney and Courtney) supports the conclusion that handgun levels of energy transfer can produce pressure waves leading to incapacitation and injury.[29][30][26][31][32] The work of Suneson et al. also suggests that remote neural effects can occur with levels of energy transfer possible with handguns (roughly 500 ftlbs/700 joules).

Click to expand...

Even though Wang et al. document remote neural damage for low levels of energy transfer, these levels of neural damage are probably too small to contribute to rapid incapacitation. Courtney and Courtney suggest that remote neural effects only begin to make significant contributions to rapid incapacitation for ballistic pressure wave levels above 500 PSI (corresponds to transferring roughly 300 ft-lbs in 12 inches of penetration) and become easily observable above 1000 PSI (corresponds to transferring roughly 600 ft-lbs in 1 foot of penetration).[29] Incapacitating effects in this range of energy transfer are consistent with observations of remote spinal injuries,[15] observations of suppressed EEGs and breathing interruptions in pigs,[27][33] and with observations of incapacitating effects of ballistic pressure waves without a wound channel.[34]

Click to expand...

https://arxiv.org/ftp/arxiv/papers/0803/0803.3051.pdf

There is a point where the hydrostatic effect comes into play. Exactly where is the question. Ive shot a bunch of the old Winchester 12 gauge foster slugs and never found a liquified chest cavity in a deer. That soft hunk of lead at 1600 fps certainly makes a good hole in and big chunk out. Seems to look like same results for guys with 50 caliber black powder guns. Look at one shot with any 2700 fps+ standard centerfire round and the lungs are a mushed. Dead is still dead, but something obviously is different.

If you want to see a long thread, start one on wounding dynamics....

Herewith, a small amount of what we know. And all of what we know is not enough to perfectly reliably predict performance.

Wounding dynamics are best modeled in terms of momentum. In an inelastic collision (bullet hitting game), momentum is conserved while kinetic energy is not.

The permanent wound channel is made by the bullet crushing and tearing tissue. A 45 ACP bullet at 850 FPS is excellent at this particular task.

There is also the temporary wound channel that is formed by stretching surrounding tissue. It snaps back into place after bullet passage, but is bruised in the process (bloodshot).

When the bullet impacts flesh, the bullet exerts force on the flesh by shedding momentum. When the bullet has lost enough momentum that it can no longer exert enough force to crush tissue, the bullet stops.

Slower bullets expend their momentum making permanent wound cavities. As bullet speed increases, the amount of momentum diverted to the temporary wound cavity increases. That is, you get less permanent cavity and more temporary cavity. It is mainly the permanent cavity transecting blood vessels that brings an animal down.

Hydrostatic shock is an oxymoron. "Hydro" means "water", and "static" means "at rest". You're going to shock an elk with water at rest? I can hardly wait to hear about the elk's reaction.

There is some evidence that there is a hydrodynamic shock, particularly if the bullet impacts at just the right point in the heartbeat cycle. I think the effect is so poorly understood that it would be difficult to say that the effect goes away below any particular impact speed.

Chuck R. said:

There's been at least one study I could find that indicates a "shock" can and does happen at less than 2200 FPS.

I was doing some research as to the "why" the .357MAG with 125grn has a favorable reputation as a "stopper". This sort of flies in the face of the conventional wisdom that "all service calibers perform basically the same with modern defensive ammo" mantra. There may be some physiological "stuff" to it. There's been at least 1 study that look at "hydro-static shock" that set the parameters at 500 ft pounds and 12" of penetration, which is pretty much what the .357 125 load delivers.





https://arxiv.org/ftp/arxiv/papers/0803/0803.3051.pdf

Click to expand...

Courtney was heavily hedging his bet on realization of "hydrostatic" shock. Although his given probability of inducing hydrodynamic ("hydrostatic") shock increases with decreasing penetration and increasing fragmentation -- he nevertheless, did not advise for much less than 12" penetration.

denton said:

Hydrostatic shock is an oxymoron. "Hydro" means "water", and "static" means "at rest". You're going to shock an elk with water at rest? I can hardly wait to hear about the elk's reaction.

Click to expand...

Whilst hydrostatic shock may not be an effect caused by high velocity projectiles (and I really couldn't say), the human body contains a hefty percentage of water. Most of which could be considered to be at rest, relatively speaking. https://www.healthline.com/health/body-water-percentage#body-water-storage

Some people know (as you probably do) that unlike air, water compresses very little. This is why explosions in water are so devastating to surrounding life. Like fishing with dynamite. The water cannot compress much, so the shock wave travels through it quite efficiently and into things that can compress. Doing damage to them.

Whether that is called "hydrostatic shock" or something else, I don't know. But it seems plausible to me that a projectile with enough velocity could cause this effect on living tissue to so degree.

WrongHanded said:

Whilst hydrostatic shock may not be an effect caused by high velocity projectiles (and I really couldn't say), the human body contains a hefty percentage of water. Most of which could be considered to be at rest, relatively speaking. https://www.healthline.com/health/body-water-percentage#body-water-storage

Some people know (as you probably do) that unlike air, water compresses very little. This is why explosions in water are so devastating to surrounding life. Like fishing with dynamite. The water cannot compress much, so the shock wave travels through it quite efficiently and into things that can compress. Doing damage to them.

Whether that is called "hydrostatic shock" or something else, I don't know. But it seems plausible to me that a projectile with enough velocity could cause this effect on living tissue to so degree.

Click to expand...

LOL.... my issue is not with whether there might be a shock effect propagating through the target. There might be. But calling it hydrostatic shock is an oxymoron. Hydrostatics is the study of fluids at rest. Think about the pressure at the bottom of a swimming pool. Hydrodynamics is the study of fluids in motion. Think about rivers and whirlpools.

"Shock" and "static" just can't go together in a description. It's like saying "Bald man with curly hair."

denton said:

LOL.... my issue is not with whether there might be a shock effect propagating through the target. There might be. But calling it hydrostatic shock is an oxymoron. Hydrostatics is the study of fluids at rest. Think about the pressure at the bottom of a swimming pool. Hydrodynamics is the study of fluids in motion. Think about rivers and whirlpools.

"Shock" and "static" just can't go together in a description. It's like saying "Bald man with curly hair."

Click to expand...

True, but one wonders how "hydrostatic shock" stuck even to the point where Courtneys' referred to their theory as "hydrostatic" shock. Of course, being Ph.D.s in physics they certainly knew better.

That action at a distance though individual particles (electrons/ ions) don't move much is also shared by a phenomenon called electricity (not static).

You can transmit a vibration through solid metal. I think we'd consider the bonds between those molecules to be static. But I'm not a scientist, so I don't really know about the terminology.

Walt Sherrill said:

My only source of round performance for M855 ammo round is Wikipedia, where one article shows the M855 5.56mm (5.56 × 45 mm) round as having a velocity of 922 m/s (3,025 ft/s).

A second Wikipedia article at military.wikia.org/wiki/5.56×45mm shows performance specs for three different versions of the M855. I don't know which version is most commonly used, but even the slowest of the three is only 30 fps below the 3,000 fps.

4 g (62 gr) 3,200 fps.
4.1g (63 gr) 3,070 fps
4.1g (63 gr) 2,970 fps​

Click to expand...

M855 is specified to have 3,000 +/- 40 fps at 78 feet, or about 3,070 fps at the muzzle, from a 20 inch test barrel.

Multiple test from multiple people/agencies show an M4/M4A1 with a 14.5 inch barrel yields about 2900 fps max.

The other Wiki values are (surprise) inaccurate. The 3,200 figure appears to be the original M193 velocity requirement, and the 2970 number is from both the Army's FM and TM, but seem to be off by about 100 fps from the Army's own actual test results.

Most, if not all, wounding is the result of improper bullet placement. I have seen deer taken cleanly with 22 LR, 357, with the hottest round being 257 Weatherby. As long as the bullet penetrates, stays intact, and is in the boiler room, velocity is moot.

From the observation of cutting up caribou.
Bullet wound channel damages meat.
A well balanced rifle like the .243 Winchester will kill a caribou without an inordinate ammount of neat damage.
The damage column is minimal like 1"
A caribou harvested by a .300 win mag leaves a channel of tainted meat the whole way
In one case the animal.was hit 3 times.
Two through the ribs and once in the shoulder.
Each rib shot threw bone shards and hemmoraged meat with a 1" size hole going in and a 3"size hole going out.
The shoulder hit had shards of bone all over the wound channel, the jelly like hemmoraged meat is very dark red/black and kinda bubbly from hydrostatic shock will bruise meat the area size of a baseball.
If you want to see what a bullet can do just hunt with it.
And besure to clean the carcass afterwards.
You will have a better understanding of what is going on on the down range end.

Walt Sherrill said:

According to Fackler and subsequent research and studies, once a round's velocity goes above 2000 fps, the secondary wound channel damage (the effect of the bullet's travel through the tissue and internal structures) becomes more significant. But, as you imply, there is no clearly defined limit which a round must exceed if it's to be effective and cause greater damage. But higher velocity alone isn't going to stop a gun fight.

Most civilian self-defense rounds have velocities in the 900-1,500 fps range. Most military long guns fire rounds that travel at greater than 3,000+ fps. and that level of performance can cause substantial damage along the bullet's path. In military conflicts a badly wounded enemy must be given medical care by his or her fellow fighters, and anyone caring for the wounded is one less fighter. Because many military confrontations/battles are extended in nature, secondary wound channel damage may play a bigger role in weakening the enemy than most realize. I think the high velocity ammo is likely to be play a more important role in military conflicts than in civilian self-defense situations if self-defense shooters have higher velocity ammo.
​

In self-defense situations the main objective is to STOP the attacker as quickly as possible. That means you can't wait for the attacker to bleed out or to realize that he or she is badly wounded, Any extra times -- even if it's just a few minutes -- may give the attacker more time to kill you, even if they are suffering or dying. And while a higher-speed bullet can make the damage done by the bullet path significantly in the person shot, unless the shooter using the hotter high velocity ammo hits something critical (like the heart, the lungs, or some part of the central nervous system) the extra damage coming from the bigger secondary wound channel damage won't necessarily change the outcome of the battle.

A higher velocity round certainly isn't a negative, but it isn't a magic bullet, either. The shooter must still hit something critical to stop the attack quickly, and if he or she can't shoot that gun and round well, it may turn out to be less effective a than less potent round in the right handgun.

Click to expand...

It took you awhile to say it, but SHOT PLACEMENT (rounds on target) IS THE MOST IMPORTANT FACTOR IN WINNING A GUN FIGHT! Or as we would tell our rookies who could not handle the full power 357 Mag, "A hit with a 38 is MUCH better than a miss with a 357." As for this discussion, hand gun ammo/performance verses rifle ammo/performance, APPLES AND ORANGES!

Jim Rau said:

...As for this discussion, hand gun ammo/performance verses rifle ammo/performance, APPLES AND ORANGES!

Click to expand...

Which I believe was the OP's original question. Why is there such a dramatic difference and around what speed does is happen? Just from my general observations it's somewhere north of 1500 fps, dont know exactly but it definitely exists.

The amount of energy increases to the square of velocity, also the resistance of flesh goes up with the velocity. as velocity the wave of energy like the waves off a boat in water become more violent and larger increasing disruption in tissue. So velocity increases tissue damage as velocity increases. Of course factors like bullet deformation have a major effect in energy transfer. Beyond 2600 FPS the type of damage dramatically increases as the ability of flesh to be displaced is exceeded. As this happens the energy is transferred radially from the wound channel, this is often referred to as hydrostatic shock. This information used to be readily available but the internet is flooded with all kinds of fake information now from people like Fackler and dozens of others with no scientific training in ballistics.

d2wing said:

the internet is flooded with all kinds of fake information now from people like Fackler and dozens of others with no scientific training in ballistics.

Click to expand...

Fackler's area of expertise wasn't ballistics, as he was a Medical Doctor. His area of expertise was the evaluation of the effects of firearms (the consequences of those ballistics) upon human tissue, and was based upon a lot of post-mortem reviews, medical studies, analysis of surgery results, and the testing of various weapons and rounds against different media, etc. Round effecitveness has improved in most calibers since his work was first undertaken, but it generally still seems valid.

I'll agree that there's a lot of FAKE NEWS out there and there always has been, but Fackler's studies don't really fall into that category of misinformation. How people INTERPRET Fackler's work is where we often get the equivalent of FAKE NEWS. Sometimes it's misunderstanding and sometimes its just people trying to discredit the results being reviewed because his study results disagree with their arugments, products, or contentions.

lysanderxiii said:

M855 is specified to have 3,000 +/- 40 fps at 78 feet, or about 3,070 fps at the muzzle, from a 20 inch test barrel.

Multiple test from multiple people/agencies show an M4/M4A1 with a 14.5 inch barrel yields about 2900 fps max.

The other Wiki values are (surprise) inaccurate. The 3,200 figure appears to be the original M193 velocity requirement, and the 2970 number is from both the Army's FM and TM, but seem to be off by about 100 fps from the Army's own actual test results.

Click to expand...

So, WIkipedia wasn't the best source. The point I was making, however, is that all of the figures cited are close to the 3000 fps target, and are still SUBSTANTIALLY higher that the some of the hottest handgun rounds (which seldom exceed 2000-2200 fps). It's also very unlikely that any really practical handgun -- a gun that most shooters can shoot well, that can be used as a self-defense weapon -- will perform as well as the typical military long gun. (Which is why military personnel carry long guns into combat, and rely on handguns much less frequently.)

I do not hunt. It makes sense to analyze and discuss velocity/wound effects if the goal is to effectively take down a large animal at long range , without excessively ruining the meat.
In self defense however , placement is king. In fact , placement may mean continued life. I believe in selecting the caliber and firearm with which the chances of putting rounds on target is maximized.

If a person is consistently missing left , the higher velocity projectile will simply fly past the intended target sooner.

If things traveling under 2200 fps didn’t have the ability to wound, people wouldn’t die in automobile, plane or train crashes or jumping off buildings and bridges, for that matter.

I have killed lots of stuff with subsonic ammunition and have never had a rimfire of shotgun round travel that fast in my lifetime.

That speed is only about 200 yards from the muzzle for 308. If I’m trying to kill something bigger than a dog at that distance I’d rather have the slower heavy bullet than a .223 moving faster.

Makes me wonder where the magic number even came from?