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So I just skimmed the Amy Courtney study, and as I thought, MacLorry doesn't jack schitt in what he is talking about. The article basically supports JB's and JWP475' initial analysis'.

Of interesting note:

"Rather than lean too
heavily on (possibly biased) expert opinions, the veracity of the
report should be determined by the degree to which the
reported results find support in other experimental findings." (page 1)

So, we see concurrence with the notion that Field Verification is critical.


"Pressure wave hypothesis:
Other factors being equal, bullets producing larger
pressure waves incapacitate more rapidly than bullets
producing smaller pressure waves." (page 1)

Of key note is the phrase "other factors being equal"....

"Applying this formula directly requires detailed
knowledge of the instantaneous mass and velocity
changes of a bullet at every point along the wound
channel." (page 2)

So that phrase RIGHT there pretty much limits the applicability of this formula in hunting scenarios. Which is sorta what JB has said all along.

Oh, did I mention that this article deals in principle with JHP handgun rounds for use on people?

"The fact that the average magnitude of the ballistic
pressure wave is inversely proportional to penetration
depth means that cutting the penetration depth in half
(for a given amount of kinetic energy), doubles the
pressure. However, this property will only increase
incapacitation up to a point, because the pressure wave
must be created inside of a visco-elastic medium and in
close proximity to major blood vessels or vital organs to
have its effect. A bullet that fails to penetrate into the
thoracic cavity or that barely penetrates might have little
effect. Once the penetration is below 9� or so, we
expect the impact of the pressure wave will be reduced" (page 3)

Placement, placement, placement.....

"The fact that Vpcc is linearly related to the penetration
depth and that 1" P is inversely related suggests that
there might be a tradeoff between the two mechanisms
because increasing penetration typically increases the
crush volume while decreasing the pressure wave.
Likewise, decreasing penetration increases the pressure
wave but typically decreases the crush volume. Perhaps
finding the �sweet spot� in this tradeoff is one key
element in designing and selecting ammunition for a
particular application and risk assessment." (page 3)

Bullet, bullet, bullet.....

"Note that, unlike the blood loss
mechanism, the probability of eventual incapacitation
with the fast mechanism is less than 100%." (page 6)

And a "energy dump" will not compensate for poor shot placement.

"Even at rifle levels of peak
pressure wave magnitude (p > 2000 PSI), a significant
fraction of deer remain on their feet for over 5 seconds." (page 7)

correlated with:

"Table 2: Pressure wave magnitude, p; eventual fast
incapacitation probability, A0; fast incapacitation
characteristic time, tf; and slow incapacitation
characteristic time, ts for Group A through Group F.
(Uncertainty in last significant digit(s) is shown in
parentheses.)
Group P (PSI) A0 tf (s) ts (s)
A 1221(86) 0.645(13) 2.94(5) 8.18(11)
B 829(60) 0.433(16) 4.14(12) 10.73(9)
C 683(65) 0.329(24) 4.82(23) 10.25(9)
D 611(42) 0.195(29) 5.13(54) 10.07(8)
E 650(53) 0.393(15) 5.36(16) 12.13(8)
F 554(57) 0.379(4) 6.56(39) 12.33(14)" (page 6)

shows that rifle bullets are not the focus of this study. Just in case some one forgot.....

"This suggests that humans are
more sensitive to pressure wave effects than deer and
goats, with the asymptotic behavior of A0 closer to 1." (page 7)

and that the scope of this study is incapacitating terrorists, not deer, or elk, or cape buffalo.

And in case the the point was lost,

"There is no contradiction, because the
data set as a whole (and thus the general trend of the
average incapacitation time in Figure 1) depends more
strongly on the slow incapacitation mechanism, which is
presumably dominated by blood loss caused by vascular
tissue damage." (page 8)

removing blood trumps energy dump in killing effectiveness.

Oh, BTW, this caveat:

"A. Cautions and Limits of Interpretation
Goats are not people, and the shot angle used in the
Strasbourg tests was particularly favorable to loads with
shallow penetration. It would be an error to infer that the
loads that worked well in the goat tests would
necessarily work well in self-defense applications with a
variety of shot angles and different penetration
requirements.

Do not be overly impressed by the propensity for shallow
penetrating loads to produce larger pressure waves.
Bullet selection criteria should first determine the
required penetration depth for the given risk assessment
and application, and only use pressure wave magnitude
as a selection criterion for bullets which meet a minimum
penetration requirement" (page 8)

Hmmmmmmm.


Thank you for the link.

Again, I am just a simple electrician, who is no way competent to argue the points of physics. But I did go to college to study history, and I do know how to read....

Jake: Good post!

+1..........

Here is one for ya...
This was a 70lb pig shot with a 204 ruger 32gr v-max.

This is not my prefered bullet for taking hogs as I like expansion, but I also like to have better penetration than the v-max offers.

The pig was facing me, just very slight quarting away, with his head down feeding. I aimed for the neck and the shot went slightly high. because of the angle this caused the bullet to impact too far back and just to the right of the spine in front of the rear leg. The bullet penetrated 8"-9" at a slightly downward and rearward angle.

The hog died instantly. Not a typical result from such a poor placement, but that is the nature of hunting. Had this pig been shot with a 338 win mag and behaved the same way I know that there would be those touting the stopping power and energy of the mighty 338.

The results:

The recoverd bullet from the pigs ham.

Good God Almighty. Where is Steelhead when you really need him?

This is pretty similar to what I've seen with that same load on deer. However, to be fair to the OGW formula, which is complete BS, it does suggest that 70 to 100 pound animals are within the capability of that cartridge.

You can all relax now as this will be my last post on this topic.

I was preparing to continue to argue my points until I read the article �Review of criticisms of ballistic ... tests, and the Marshall and Sanow data�. Anyone reading this article will quickly conclude there's an on-going heated debate within the scientific community regarding the mechanisms by which bullets quickly incapacitate and kill. Fackler and MacPherson seem to be on one side of debate and a slew of other researchers are on the other side as evidenced by the paper Scientific Evidence for �Hydrostatic Shock�

If the experts can't agree or even be civil with each other there's no hope of doing so here.

The University of Utah hosts an on-line Firearms Tutorial. Here�s the section on Ballistics. Scroll down to Terminal ballistics and note that nearly every point being made is referenced back to scientific research which is detailed in the reference section. for anyone wanting to check the original research.

Another resource is the Terminal Ballistics page. It covers a wide range of data and the author may be a member of this forum as he writes �Discussion of Incapacitation has been known to get quite heated. In fact it often degenerates into personal attacks and name calling.� While the focus is on handguns, he does reference hunting as well. I think many will agree with his "Five Ps": Placement, Penetration, Physical Damage/Wound channel, Power/Energy, and Psychology.

Some may be interested in Hornady Terminal Ballistics

Sorry if I ruffled feathers, stirred up the dust, and woke up the sleeping dogs. Look on the positive side, this discussion has certainly helped many increase their post count.

As long as we're reading stuff......


...........Cary asked him "How many elk have you killed with a 270?",expecting him to say perhaps a hundred. Forgett replied, "Over a thousand." He also told Cary that the 250 Savage and 257 Roberts were too light for elk;the 30-30 was effective only to about 150 yards when pointed well;the 30-40Krag and the 300 Savage were good and the 30/06 very effective........the 300H&H and the 375H&H,though good killers,were more gun than needed.......

Lucian Cary of TRUE magazine, interviewing Bill Forgett,a control hunter for Colorado F&G,in 1951.......Forgett tried rifles from the 220 Swift to the 375H&H but came to prefer the 270 with 130 gr bullets.......

Article by Fred Barker....Precision Shooting-October 2004.

Some stuff just never changes......

Funny thing Bob,
A friend who use to work as a predator control officer came to the same conclusion after trying every thing from .38 spec. (on trapped bears) up to the .458 mag.
He shot a bunch of dump bears every year and didn't want runners.

His favorite cartridge for that job was a .270 loaded with the old Winchester Silver Tip..
The .338 mag was his second choice..

Later on in life he mused the reason that they worked so well was that when the .270 and the .338 mag came out the bullets made for them were designed for their working vel. as they were the only cartridge in their respective cal. at the time..

Nrut: I think when it comes to this stuff, some things defy numbers......

We can only find this out shooting animals....

Wise decision Mac. The subject of terminal ballistics is to hunting what politics and economics are to the general public. Everyone has an opinion they believe is fact or is supported by the facts.

If nothing else you've shown that there are reputable scientists who believe hydrostatic or hydraulic shock is an important component of rapid incapacitation. I see these scientists give their e-mail address in the papers you linked to, so those who want to argue the physics can now do so with someone who has a PhD in physics.

As for me I�m going to go argue politics with rattlesnakes

The one cartridge that I personally believe through experience and the experience of trusted others that negates this OGW theory is the 22LR. God only knows what the record is but I'm sure that for bullet weight/powder charge/mv/ke/whatever it's killed WAY out of proportion to its size more than any other cartridge.

As a non-hunter who has training in physics (B.S. from MIT) and has published papers in scientific and medical journals, let me stick in my 2 cents.

1) The best theory is the one that fits the observed facts the best. if the facts don't fit the theory, you must either revise it or discard it. That is a basic rule of science, and engineering is based on science.

2) Would you shoot a game animal with a bullet that hits with less than 100 ft-lb energy? As Finn Aagaard once pointed out, an arrow that has less than 100 ft lbs energy kills quite well when it hits the heart-lung area. What does that say about kinetic energy as a measure of killing power?

3) In the absence of a well validated and agreed upon theory, you go with experience and observation.

4) So, as I'm not a hunter, let me quote from two old, experienced hunters/writers that I have a lot of respect for, and who have passed on to the Happy Hunting Grounds:

"I have some more news: game is not killed by foot-pounds of energy. In fact, the energy has little to do with killing power. Animals are killed by putting in the right place a bullet that penetrates deep enough and opens up adequately."


"Proper bullet placement + sufficient penetration = quick, clean kill.

That, really, is all one needs to know about killing power."


The first quote is from Jack O'Connor in the Gun Digest 1974 article on the 7x57 Mauser.

The second quote is the conclusion to an article by Finn Aagaard on Killing Power Myths in Rifle Magazine.

To me, these comments, added to those of JB and other experienced hunters here, make a lot of sense. When you have several experienced people coming to similar conclusions, you got to listen. So, if and when I ever get to go hunting I will practice my marksmanship, take an adequate caliber with a good bullet, try to get close enough to place my shot accurately in the proper place, and hope to come home with some wild game meat after a clean kill. As the fellow said, I may be wrong, but at least I'm in good company!

As someone who has a B.S. from MIT maybe you�ll be interested in the following two papers published by someone who has a PhD from MIT.

Ballistic pressure wave contributions to rapid incapacitation in the Strasbourg goat tests

Scientific Evidence for �Hydrostatic Shock�

I�m not going to argue the point, but being able to kill something by putting an arrow, knife, or spear through the heart doesn�t disprove the ability of large and rapid energy dumps being able to damage the central nervous system as the above studies claim. Problem is the folks on this forum can�t even agree on the basic physics of a bullet dumping energy into the target, or not. My conclusion is that this subject is the equivalent of religion to hunters and no one is going to change anyone�s mind about what they believe.

I would like to see proof of the Strasbourg tests ever taking place. Dr. Fackler hS STATED THat the pressure wave isn't high enough to cause incapacitation especially at handgun velocities

This article answers the criticisms of Fackler and others concerning the Strasbourg goat tests and the Marshall and Sanow data.

I�m not suggesting that any of this should change anyone�s mind, only that it shows researchers with even better formal credentials than Fackler disagree on the physics. You know what works for you, just as I know what works for me. I can live with that.

I am not convinced of the tests in the first place since they can not be confirmed and Marshal and Sanow were mag writers about cars before they suddenly became "terminal bullet performance" experts

And what Amy Courtney wrote:

"Note that, unlike the blood loss
mechanism, the probability of eventual incapacitation
with the fast mechanism is less than 100%." (page 6)


"There is no contradiction, because the
data set as a whole (and thus the general trend of the
average incapacitation time in Figure 1) depends more
strongly on the slow incapacitation mechanism, which is
presumably dominated by blood loss caused by vascular
tissue damage." (page 8)

"A. Cautions and Limits of Interpretation
Goats are not people, and the shot angle used in the
Strasbourg tests was particularly favorable to loads with
shallow penetration. It would be an error to infer that the
loads that worked well in the goat tests would
necessarily work well in self-defense applications with a
variety of shot angles and different penetration
requirements.

Do not be overly impressed by the propensity for shallow
penetrating loads to produce larger pressure waves.
Bullet selection criteria should first determine the
required penetration depth for the given risk assessment
and application, and only use pressure wave magnitude
as a selection criterion for bullets which meet a minimum
penetration requirement" (page 8)

Which just goes to show that some people can't give up a losing argument.....

As far as I can see these are papers that were submitted for publication several years ago. Were they actually published somewhere - because for a paper to be published it has to be submitted for peer review and approved by the peer reviewers and the editor for publication, which means that other experts in the field (peers) agree that it is worth publishing and the editor has to agree. The fact they were revised means that they were altered to answer criticisms from reviewers, but generally if they were accepted for publication it will so state, along with the date of acceptance. If these were NOT published that means they were not considered to be significant contributions to the field. Unpublished papers don't mean anything beyond the personal opinions of the authors.