Certaindeaf
member
The only time foot pounds of energy doesn't "count" is for some of the games where numbers/formulas have to be jiggered to make "major", thus making your .45 viable. lolz
Well, all else being equal. A heavier wadcutter isn't going to run down a boat-tail spitzer just because it's 10 grains heftier.
Quote:
Originally Posted by CZ57 View Post
Well, I'm glad you could find 1 example. There are +P loads available from Double-Tap, Buffalo Bore that are rated 1125 FPS or higher and Underwood Ammo has a 147 gr. JHP rated at 1175 FPS and +P+. They all use bonded bullets. Stick that in your theoretical Mcpherson modeler.
Now, now......there's no need to be rude. I'd remind you of rule 4 of the THR CoC, posted here for your convenience-
4. Spamming, trolling, flaming, and personal attacks are prohibited. You can disagree with other members, even vehemently, but it must be done in a well-mannered form. Attack the argument, not the arguer.
Do try to be civil.
If you have misgivings or lack an understanding of these models (Schwartz, MacPherson), you might do yourself a favor and read one or two of the two books.
What is not considered in the model is the point where expansion begins, rapidity of expansion, the larger temporary stretch cavity created causing a larger Total Wound Volume.
So now your the conduct police because you know what the result of using the higher energy loads will do in the modeler? Who's being rude? All I said was "stick that in your MacPherson modeler". I think everyone here can recognize someone's attempt to be a subtle smartass.
MacPherson's theories put forth the notion that bullets behave like flying drill-bits. I guess that's because he's a mechanical engineer as well as a Facklerite. It seems that anyone with an interest can become a terminal ballistics expert these days. But go back to the case of the 147 gr. HST vs. the 147 gr. +P HST, since that's the load you seem to understand. The +P penetrates only 3/10" deeper and by MacPherson's model all that will achieve is to cut the wound cylinder by 86% of recovered diameter with a depth of 3/10" in addition to the permanent crush cavity created by the standard pressure 147 gr. HST. That's it and all he considers.
What is not considered in the model is the point where expansion begins, rapidity of expansion, the larger temporary stretch cavity created causing a larger Total Wound Volume. Again, without the actual representation showing the two rounds fired into ballistic gelatin your assumptions are simple hyperbole.
I only introduced the Critical Duty 135 +P into the conversation as a lower recoil option for those that may be recoil sensitive. But at least there is actual gel tests that can be viewed at the Hornady site. You, on the other hand have provided nothing but conjecture along with a recommendation to read two books. One of which I already know to be seriously flawed.
I also posted a link to m4carbine.net where anyone can go to see a ballistic gel test of various loads including on of the better performing standard pressure 147s and a standard pressure 124. No need to even see a 124 +P because the standard pressure 124 is out performing the standard pressure 147. There, at least, the viewer can decide for himself which is the better performing load.
One thing I can say for the 147 gr. JHP is that it's sectional density is very high due to it's length and .355" diameter. It is actually less dependent on KE than the 124 because it is capable of higher momentum at the right velocity. So lets use the simple method of comparing power factor of the two loads that is fairly representative of momentum. Your 147 gr. HST with a muzzle velocity of 1000 FPS has a power factor of 147. I'll use the example of the SPEER 124 gr. +P Gold Dot which is rated 1220 FPS at the muzzle and has a power factor of 151. The 147 develops 326 Ft/Lbs of KE at the muzzle. The 124 gr. +P Gold Dot develops 410 Ft/Lbs at the muzzle. So not only does the 124 have a greater amount of KE it also provides higher momentum than the 147 that's more dependent on momentum for expansion. The differences can be seen by examining rounds fired into %10 ballistic gelatin. So if I expected a 147 to perform as well as a 124 +P, I'd choose a 147 gr. +P.
And what I meant about "serious shooters" is that anyone contemplating carrying a handgun for self defense should be able to master the 124 gr. +P. They should practice until they can. If that doesn't work and you still decide to carry concealed, then go with a standard pressure 147. And before someone brings up something like accelerated wear by use of +P ammo, I'll remind everyone that when I started shooting and handloading 9mm, there was no +P. There was the pressure standard that had been in use since 1902 and that is 35,700 CUP. Test a similar load by the SAAMI PSI method and you'll find it achieves about 38,500 PSI. The SAAMI rating for +P. The European standard of 36,200 PSI CIP is almost an identical pressure they just use a slightly different test method. You can bet that any quality American or European manufactured 9mm Pistol is designed around the original pressure standard of 35,700 CUP. The difference being that pistols intended for the American market are sprung lighter.
Both controlled by bullet design, not by fifty or a hundred feet per second here or there.
I don't think a temporary stretch cavity caused by bullets of the size, weight, and speed we're talking about here have much impact on the final wound either. Flesh is plenty elastic.
Bullet design accounts for the differences between final measurements of handgun wounds far more than specific weights and velocities do.
This is where the KE model falls apart;
http://www.glocktalk.com/forums/showthread.php?t=336612
Compare the KE advantage of the 10mm/180gr Gold Dot with the 45auto/230gr Gold Dot, same penetration and expansion. Check the 230gr Gold Dot with the uber high velocity 9x25mm/125gr Gold Dot, slight penetration advantage for the 45auto, but a sizable crush cavity advantage for the heavy and "slow".
“. . . every now and then someone wants to analyze or think about a problem involving energy, and when they attempt to do this without really understanding energy or other thermodynamic concepts the result is unfortunate. One such problem is the analysis of any of the various aspects of terminal ballistics; some individuals with inadequate technical training and experience have unwisely and unproductively attempted to use energy concepts in the analysis of bullet impact and penetration in soft tissue. (Many others have simply assumed that energy is the dominant effect in Wound Trauma Incapacitation; this assumption is even more simplistic than the attempt to actually analyze the dynamics problem with energy relationships, and is no more successful).
Any attempt to derive the effect of bullet impact in tissue using energy relationships is ill advised and wrong because the problem cannot be analyzed that way and only someone without the requisite technical background would try. Many individuals who have not had technical training have nonetheless heard of Newton’s laws of motion, but most of them aren’t really familiar with these laws and would be surprised to learn Newton’s laws describe forces and momentum transfer, not energy relationships. The dynamic variable that is conserved in collisions is momentum; kinetic energy is not only not conserved in real collisions, but is transferred into thermal energy in a way that usually cannot be practically modeled. The energy in collisions can be traced, but usually only by solving the dynamics by other means and then determining the energy flow.
Understanding energy and how it relates to bullet terminal ballistics is useful even though energy is not a useful parameter in most small arms ballistics work.”
While a projectile in motion possesses both momentum and kinetic energy, the penetration of a transient projectile through a homogenous fluid or hydrocolloidal medium constitutes an inelastic collision mandating that it be treated as a momentum transaction. Therefore, a momentum-based analysis of projectile motion is the most equitable approach in constructing a terminal ballistic performance model. Although it may be possible to devise a mathematical model based upon the expenditure of a projectile’s kinetic energy as it traverses a medium, there is nothing to be gained from the pursuit of such an unnecessarily complex approach.
In post #63 you used Double Tap, Buffalo Bore and Underwood ammunition to support a statement, yet you didn't post any ballistic gel pictures. I post DT's gel data and now you need pics, why the double standard?I guess I don't get it. At the link you provided I don't see any gel test pics, just a list of cartridge performance after passing through four layers of denim and two layers of light cotton.
Both the rounds you mention penetrate to 15.25". The 230 gr. Gold Dot expands to .95" and the 180 gr. 10mm expands to .96". According to the beliefs of experts like Fackler, MacPherson and Roberts, you throw energy and temporary stretch cavity out the window and in this case the 180 gr. 10mm by their standards would be the better stopping load by virtue of .01" greater expansion.
Sure you can. You can shoot the test medium with a 125 grain .357 and then logically, all ammo that didn't perform like that/have those characteristics would essentially be inferior since it's the undisputed stopper..If you don't accept MacPherson's research, then you can't use ballistic gel as a test medium..
In post #63 you used Double Tap, Buffalo Bore and Underwood ammunition to support a statement, yet you didn't post any ballistic gel pictures. I post DT's gel data and now you need pics, why the double standard?
It's interesting that you should denigrate MacPherson and at the same time want pictures of bullet performance in ballistic gel. Guess what, it was MacPherson who did the research, bullet testing and came up with the formulas that validated Fackler's ballistic gel composition as a soft tissue simulant. It doesn't seem to me that a person who conducts the tedious and time consuming tasks of shooting 400 rounds of ammunition, into an aggregate total of a ton of ballistic gel, be considered a theorist.
You can't have it both ways, if you accept the use of ballistic gel as a medium to determine bullet penetration in soft tissue, then you accept MacPherson's research. If you don't accept MacPherson's research, then you can't use ballistic gel as a test medium.
Either accept MacPherson's kinetic energy quote as posted by 481 or find a testing medium other than ballistic gel. BTW, MacPherson's book has pictures of bullets in it, the book by Schwartz doesn't, but both are excellent references for those who wish to intelligently discuss terminal ballistics.
The purpose and composition of ballistic gel is to measure bullet penetration in soft tissue, that's all.
There's a lot of excellent information at this website, I linked to this "myth" chapter because of its appropriateness to this thread.
http://www.rathcoombe.net/sci-tech/ballistics/myths.html#energy
Theory and conjecture. Thanks for pointing out that MacPherson is an aerospace engineer. He should stick to his trade.
His hypothesis are only tested by theoretical models, or are directly traceable back to the philosophy of Martin Fackler.
And for those that don't know, it was Martin Fackler's theories dominated by penetration that led the FBI and other LE agencies to choose the 147 gr. JHP 9mm load in the late 80s. These rounds failed to provide adequate expansion and in some cases innocent bystanders were struck by overpenetrating bullets.
Then came the "10mm Lite" based on the same principles dominated by penetration that proved to be only a marginal stopper in actual shootings.
Next on the Fackler hit parade came the "Medium Velocity" 165 gr. JHP load in .40 S&W. Another lackluster performer that didn't last long. All of this at taxpayer expense, by the way. Rather than correct his own mistakes, Fackler and his followers began a crusade against the data collection method of Marshall & Sanow. Two police officers and laymen that simply compiled reports where only one shot was required to stop a fight by LE officers across the country.
Why is that any better of a prediction than actual gelatin tests through various barriers and actually seeing the performance in what has proved to be relatively reliable simulations?Consider this:
We're talking about self defense, so we're talking about shooting human threats.
With that in mind....
There is no way to reliably predict the penetration of any given round in a shooting.
There are far too many variables at play (size of the threat, body composition of the threat, angle of the shot in relation to the threat's body, clothing worn by the threat, etc...).
There is no way to reliably predict the expansion of any given round in a shooting.
Again, too many variables.
But one can buy ammo that can reliably offer an approximate muzzle energy.
So, why would one discount energy in favor of other far less reliable factors?
easyg said:But one can buy ammo that can reliably offer an approximate muzzle energy. So, why would one discount energy in favor of other far less reliable factors?
That's a good point, 1858.I think it's fair to assume that the FBI is under considerably more pressure to "get it right" than the rest of us, and they don't select ammunition based on muzzle energy.
481 said:I do not believe that there is a KE requirement in the FBI test procedure.