Home Forums Hunting & Shooting Ask The Gunwriters Exposing the Foot Pounds of Energy Myth

And yet it sells! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

Great post,and that is the crux of this thread

Very true, a .22-250 varmint round can stop a grizzly cold if it happens to expend all of its energy in the heart lung area. The thing is, though, that such a round will likely expend all of its energy on the shoulder blade or rib cage, before reaching the vitals. That's why bullet construction, weight, and sectional density must also be considered, not mere ft lbs of energy. A six inch long .22 caliber FMJ bullet travelling at 3,000 fps, for example, would have huge amount of energy with it, but would likely make a tiny clean hole through a deer, imparting most of its energy on a rock formation a hundred yards behind the animal.

A good post Hawkeye

Another example would be a 300 RUM with a 180 grain at 3300 FPS,the energy would be 4353 FPE,compared to a 375 H&H with a 300 grain slug at 2530 FPS wich is 4265 FPE. If I were after Cape Buffalo or larger game my choice would be the 375H&H even though the 300 RUM has a muzzle energy that is 88 Foot pounds more. This is the problem of useing foot pounds of energy to compare one cartridges effectiveness to another

This quote from:


quote:
WHAT'S WRONG WITH THE WOUND BALLISTICS LITERATURE, AND WHY

by M.L. Fackler, M.D.

Letterman Army Institute of Research
Division of Military Trauma Research
Presidio of San Francisco, California 94219

Institute Report No. 239
July 1987



quote:
4. Presumption of "Kinetic Energy Deposit" to Be a Mechanism of Wounding:
Serious misunderstanding has been generated by looking upon "kinetic energy transfer" from projectile to tissue as a mechanism of injury. In spite of data to the contrary (1, 63), many assume that the amount of "kinetic energy deposit" in the body by a projectile is a measure of damage (2-5, 36, 37, 40). Such opinions ignore the direct interaction of projectile and tissue that is the crux of wound ballistics. Wounds that result in a given amount of "kinetic energy deposit" may differ widely. The nondeforming rifle bullet of the AK-74 (Fig 6) causes a large temporary cavity which can cause marked disruption in some tissue (liver), but has far less effect in others (muscle, lung, bowel wall) (9). A similar temporary cavity such as that produced by the M-16 (Fig 2), stretching tissue that has been riddled by bullet fragments, causes a much larger permanent cavity by detaching tissue segments between the fragment paths. Thus projectile fragmentation can turn the energy used in temporary cavitation into a truly destructive force because it is focused on areas weakened by fragment paths rather than being absorbed evenly by the tissue mass. The synergy between projectile fragmentation and cavitation can greatly increase the damage done by a given amount of kinetic energy.

A large slow projectile (Fig 7) will crush (permanent cavity) a large amount of tissue, whereas a small fast missile with the same kinetic energy (Fig 4) will stretch more tissue (temporary cavity) but crush little. If the tissue crushed by a projectile includes the wall of the aorta, far more damaging consequences are likely to result than if this same projectile "deposits" the same amount of energy beside this vessel.

Many body tissues (muscle, skin, bowel wall, lung) are soft and flexible--the physical characteristics of a good shock absorber. Drop a raw egg onto a cement floor from a height of 2 m; then drop a rubber ball of the same mass from the same height. The kinetic energy exchange in both dropped objects was the same at the moment of impact. Compare the difference in effect; the egg breaks while the ball rebounds undamaged. Most living animal soft tissue has a consistency much closer to that of the rubber ball than to that of the brittle egg shell. This simple experiment demonstrates the fallacy in the common assumption that all kinetic energy "deposited" in the body does damage.

The assumption that "kinetic energy deposit" is directly proportional to damage done to tissues also fails to recognize the components of the projectile-tissue collision that use energy but do not cause tissue disruption. They are 1) sonic pressure wave, 2) heating of the tissue, 3) heating of the projectile, 4) deformation of the projectile, and 5) motion imparted to the tissue (gelatin bloc displacement for example).

The popular format for determination of "kinetic energy deposit" uses a chronograph to determine striking velocity and another to determine exit velocity. A 15-cm thick block of tissue simulant (gelatin or soap) is the target most often used. This method has one big factor in its favor; it is simple and easy to do. As for its validity, the interested reader is referred to wound profiles shown in Figs 1-7. Comparing only the first 15 cm of the missile path with the entire missile path as shown on the profiles shows the severe limitation of the 15-cm block format. The assumption by weapons developers that only the first 15 cm of the penetrating projectile's path through tissue is of clinical significance (64) may simplify their job, but fails to provide sufficient information for valid prediction of the projectile's wounding potential. The length of bullet trajectories through the human torso can be up to four times as long as those in these small blocs. Even if this method were scientifically valid, its use has been further flawed by nearly all investigators who have included the M-16 rifle bullet in those projectiles tested. This method assumes that the projectile's mass remains constant through both chronographs. The M-16 routinely loses one third of its mass in the form of fragments which may remain in the target (see Fig 2). The part of the bullet that passes through the second chronograph screens weighs only about two-thirds as much as the intact bullet that passed through the first set of screens. No provision is made for catching and weighing the projectile to correct for bullet fragmentation when it occurs. The failure to correct for loss of bullet mass can cause large errors in "energy deposit" data (8).

Surgeons sometimes excise tissue from experimental missile wounds that is, in their judgment, nonviable and compare the weight of tissue excised with the "kinetic energy deposited" (65). A surgeon's judgment and his technique of tissue excision is very subjective, as shown by Berlin et al (66), who found in a comparison that "One surgeon excised less tissue at low energy transfers and rather more at high energy transfers than the other surgeon, although both surgeons used the same criteria when judging the tissues." None of these experiments included control animals to verify that tissue the surgeon had declared "nonviable" actually became necrotic if left in place. Interestingly, all studies in which animals were kept alive for objective observations of wound healing report less lasting tissue damage than estimated from observation of the wound in the first few hours after it was inflicted (43-47, 67, 68). In a study of over 4,000 wounded in WW II it was remarked, "It is surprising to see how much apparently nonvital tissue recovered" (69).

Anyone yet unconvinced of the fallacy in using kinetic energy alone to measure wounding capacity might wish to consider the example of a modern broadhead hunting arrow. It is used to kill all species of big game, yet its striking energy is only about 50 ft-lb (68 Joules)-- less than that of the .22 Short bullet. Energy is used efficiently by the sharp blade of the broadhead arrow. Cutting tissue is far more efficient than crushing it, and crushing it is far more efficient than tearing it apart by stretch (as in temporary cavitation).



Seems to me that kinetic energy as applied to firearma is poor way of rating effectiveness

jwp;

Serious question: Are you on a crusade, or something?

KE alone is a [bleep] measure of effectiveness, true. Just like caliber alone, or projectile weight alone, or any other factor alone.

Still, compare apples to apples, and something like, say, the .300 Savage firing a 180 gr. PSP vs. a .300 Wby firing an indentical 180 gr. PSP and which is going to be the better big-game cartridge? The only difference between those two (assume like rifles, Rem 700s, for instance) is going be be velocity, and thus energy. Identical bullets, identical calibers - greater velocity and energy in one vs. the other.

The Dr. Fackler report has been long published on my website with the knowledge of and direct permission from Martin Fackler, MD. All proper references and credits are included:

What's Wrong with the Wounding Ballistics Literature, and Why

There are several factors that are discussed from the basis of empirical evidence from Dr. Fackler, himself an experienced battlefield surgeon. Those interested in such matters might as well read the entire content.

There are an estimated 30 MILLION deer in North America. Hunters tag some 5-6 million every year, so we must be doing something right. There are another 1.5 deer / vehicle accidents per year; I'd imagine the Buick / Bambi lethality percentage is quite high. We have another 1 million or so deer that are poached every year-- there are no official numbers on that, obviously. We have yet another unclaimed wounded / gutshot deer in North America that die due to wanton waste. There are more taken by depredation permits in certain areas.

Some 9- 10 million deer a year dying from causes other than 'natural.' Still the deer populations grow, as does the annual deer harvest most years. Every year, we intentionally kill over 6 million deer-- most rational people would call this more than a trival sampling, or simple phone survey. By now, we should certainly know what causes a deer to die. And, we do.

Unfortunately, it is not the one word answer that everyone seems to want. "Velocity kills. Energy kills. Expansion kills. Sectional density kills. Caliber kills." We really should know by now that there is no simplistic answer to a sophisticated question.

Anyone that has taken a first year biology course knows what the vital organs of a mammal are. Remove or destroy a vital organ, the animal quicky perishes.

From the medical autopsies on deer, the videotaped killing and subsequent medical autopsies on live deer, hogs, mules, goats, we do know a few things.

We know that no two wild animals are exactly alike. Animals are individuals, with wide variances in strength, health, and the will to live. What may instantly drop a certain deer may not do the same on a deer of similar size and shape.

Not only are all wild animals different, but no two wound cavities are identical. Same rifle, same range, same bullet, same shot placement-- yet, a different wounding profile. Always.

It should strike us as a bit silly when the tissue simulants we use are concocted to be the SAME, whether calibrated ballistic gelatin, soaked phone books, putty, soap, soil, water, and endless variants. None of them have circulation, respiration, or living tissue-- or even bones. It is never enough; have you made a "Ballistic Buffalo" yet? Ballistic Buffalo

No tissue simulant known yet can approximate the elastic characteristics of living tissue, or accomodate health, age, and will to survive into any precise equation.

We will continue to worship velocity, expansion, energy, section density and other fragmented parts of the equation as always. We should really know better.

Look at ALL the lethality formulas. Here is a collection of them from one load, a REAL LOAD, a load I hunt with on a regular basis. Can anyone tell me what game animals it is good for, and at what ranges? Yet, here are many of its "sometimes accepted" values:

Hatcher�s RSP = 120.4

A-Square Penetration Index = 41

A-Square Shock Power Index = 539

Tappan�s WAVE factor = 120.4

IPSC Power Factor = 665

Lott�s Estimated Effective Energy: EEE1=306 EEE2=1497

Taylor Knock-Out Value = 43.5

Fuller Index = 175

Wootter�s Lethality Index = 306

Arnold Arms Relative Performance Index = 96

Elmer Keith Knockdown Factor = 95 pounds / feet.

Parker Ackley�s Momentum = 66.5

All of these values are more sophisticated, some FAR more than just energy numbers. Yet, none of them are anything less than tremendously flawed-- for a couple of so very obvious reasons.

This stuff is apparently quite good for Al Gore's Internet, though. <img src="/ubbthreads/images/graemlins/smirk.gif" alt="" />

[quote] KE alone is a [bleep] measure of effectiveness, true. Just like caliber alone, or projectile weight alone, or any other factor alone.[quote]

You are exactly correct here,that is the myth of foot pounds of energy as a way of measuring one calibers effectiveneass to another.
There are many variables,(speed ,bullet diamater,bullet construction, etc)
Just trying to say that foot pounds of energy is not the best way to determine the effectiveness of a rounds ability to incapacitate,there are other considerations

GREAT POST

There's the crux of the matter, where (IMO) it's stupid to waste time and thought. With all the inevitable, substantive variations unavoidably involved, it's simply impossible to construct any kind of useful or accurate numerical equation or rating system � so why bother? There'll always be a great number of typical exceptions that anyone can expect to encounter in the field, at any unpredictable time.

This quest is therefore about as useful as the debate about how many angels can dance on the head of a pin.

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When all else fails, invent a caliber.
<img src="/ubbthreads/images/graemlins/cool.gif" alt="" />

If you are suggesting that increasing the fpe will always increase the effectiveness, you are just plain wrong. Take a standard construction soft pointed 180 grain .30 caliber spitzer bullet and hit a bull elk with it in the shoulder at exactly 2,000 fps. Then take the exact same bullet and hit another bull elk, same weight in same spot, but this time at 4,000 fps. The second bullet will make contact with greater fpe, yet have a less deadly effect on the animal, because the bullet will disintegrate against the shoulder, wounding the animal instead of killing it.

OK, OK...YOU WIN....F***IN' LET IT GO! SOMEBODY TELL ME WHERE TO GO BUY A BIG BORE THAT WILL KILL! ALL I HAVE IS "POTENTIAL TO DO WORK" CARTRIDGES THAT HAVE BEEN MYTHICALLY KILLING DEER FOR 25 YEARS, HELP ME STOP THE MADNESS!

TRH;

Weren't suggesting that at all - it was just the first nearest apples-to-apples comparison I could come up with.

Ken's post, and Randy's earlier treatise said it best, methinks... after those, this horse is just about dust...

+100000000000000000000000000000000000

My thoughts exactly.

How is it any less meaningfull than this caliber vs that caliber??
Learning and understand the dymamics of wounding can perhaps make us all better at our passion of hunting big and small game

Friggin' leeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiit goooooooooooooooooooooooooooooooooooo!

Same to you if you like it DON'T participate

So does this mean that perhaps we can also probably learn more about love and attraction by assigning a "beauty index" or "sex-appeal factor" to each of our favorite Hollywood "Heavenly bodies" and even rate our girl friends accordingly? <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

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