The real science behind Quantitative Ammunition Selection comes from predicting penetration and statistics by firing into water. It will accurately predict performance in FBI controlled testing with a confidence factor above 95% with 900 loads tested. Let me explain something here: I don't gain anything financially from sharing this info. It is simply the best method for testing and evaluation I've seen in my 40+ years of reading other opinions on the subject vs what I've seen with my own 2 eyes.
Let me explain, if I can; QAS is not about a comparison to anything other than the results by firing and recovering the bullet tested, in comparison to FBI gel testing. So let me stop right there. How many parameters is your defense load capable of improving upon? How many parameters should you be concerned about? To my way of thinking, the high capacity advocacy is about how many rounds you can fire accurately in a small segment in time while there might be multiple adversaries.
Just when I thought the Speer 124 gr +P Gold Dot was the favored by all Law Enforcement, I saw that Hornady seems to have made them a 135 gr. load rated +P @ 1110 FPS that's on the menu. I dunno, maybe James Comey mandated such a load. IMO, I wouldn't even bother except that I did test where the velocity spec was not reached, even from a longer barrel while expansion isn't much in comparison to better JHP loads in 9 x 19mm. The actual numbers for such a load I won't even investigate beyond muzzle energy and momentum while it does get above the .6500 Lb-second minimum momentum requirement of any defense load I'd choose for myself, but expansion and every other data point will not be favorable.
Over the past 3 decades, people advocating penetration (and with tunnel vision) were right in one respect, or 1/2 correct: a minimum depth of penetration is required. But that's only half the science where the Hornady 135 gr. +P Critical duty load only generates 369 Ft/lbs of muzzle energy even if it could match its overly optimistic velocity spec. Don't even ask me about screwdriver bullets; I won't be offering data for an opinion. I'll just say that they're not for me. Subscribe to your favorite guru if you want, but you can do better by testing for yourself for any load you contemplate for a carry load. I've already mentioned the shortcut I take in water testing, and it is different than how Charles Schwartz conducts his tests, but I do not want to see an expanded JHP penetrating completely through 4 1-gallon water jugs. My minimum is through 2 jugs and well into the 3rd, and that standard was established by what some might not even consider worthy, with the Winchester 230 gr. JHP White-Box load, where with lighter bullets, more velocity is gonna be required, accordingly, to match that load's momentum at around 850 FPS delivering .8680 Lb-seconds.
It might be fairly considered that water testing is harder on JHP performance than any other medium involving gel of one kind or another. And as I mentioned, penetration is but 1 data point that I want to consider where 12" without barriers is fine by me. Shoot through 4 layers of denim? The same load will penetrate even greater.
Summation: I ain't gonna choose a defense load based on how it rates in FBI tests. Job #1, without a close 2nd is shot placement. That to be followed by a an equal consideration of penetration, energy and momentum. I don't practice contingencies like what occurred to the FBI in Miami 1986, and needing to consider 18" of penetration. My practice is, and always has been about the best accuracy C.O.M. also known as center-of-mass, and shooting until the threat is stopped. And as far as Miami 1986 goes, 12" of penetration might have prevented a great deal of speculation rather than science. Had the FBI chosen the load advocated and originated by Peter Pi of Cor-Bon just shortly after, 10mm Lite/subsonic, .40 S&W Lite/subsonic, and then going back to 9mm . . . think about the taxpayer money.
The thing is, there's a really easy way to evaluate your defense loads. You do not have to be a handloader, but you will need access to a chronograph that maybe a shooting buddy has, if you don't want to invest $100 to do it yourself. Other than velocity, diameter and weight of the recovered bullet can tell you what you really want to know.
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