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Quantitative Ammunition Selection: Ballistic Science I can Use!

 

chuck bookBy Kevin Newberry

It has been a few years since I first saw mention of the excellent book authored by Charles Schwartz. I must admit that at first I was skeptical, nonetheless, I kept seeing things posted on various handloading forums that appealed to me so I went to the website to investigate. I got the gist of things, or so I believed, that validated some of my own experiences, many, not so scientific. Unfortunately, between my full time work as a designer, writing articles for this E-mag, posting on gun forums and moderating the ammo and reloading sub-forum for one of them combined with my continued writing of fiction left me little time for anything else. It has been some time since I’ve read any book, fact or fiction. That has recently changed for the better.

Rather than detail things in great length and possibly disclose proprietary data, I’ll just cover some events and the effect that this research has had on me, personally. Not to keep anyone dangling, I’ll mention that Charles Schwartz found his way to some of my articles here and took me up on the invitation to join us at the relatively new gun forum: The Gun Rack. As soon as I saw him posting under his own name I had to send a personal message asking if he was the Charles Schwartz I hoped he would be. I was delighted to find that he was, and how he came to find us at The Gun Rack. So, it is with great pleasure for me to announce that this article is something of a segue. Chuck will follow with articles of his own.

Kilroybig72  After exchanging personal messages at the forum, many of them Q&A, Chuck offered to send me a PDF copy of Quantitative Ammunition Selection that at this point I’ll reference as QAS. In exchange for his generosity, I sent him a PDF copy of my novel, Kilroy: Kilroy Was Here.

After reading QAS, the Q&A dialogue intensified. Sometimes from the perspective of a “Doubting Thomas.” Chuck helped me along immensely covering things that he had researched during his journey, some of which I was unfamiliar with. That culminated with him sending me a spreadsheet to run his Q Model, which naturally, I tried to over complicate. The Q Model is quite easy to run with just a few data points being required for input. It then predicts things like Depth of Penetration, Wound Volume and Mass; then you get to predictions for incapacitation by the number of successive rounds fired. The final item that clinched it for me is the amount of energy expelled by an expanding JHP from 1 – 15 centimeters into the medium and why I felt compelled to write this article. All of which can be determined from using water as the test medium. While at his website I saw the rating for accuracy at 95%, (or r = +0.94) to that of testing with calibrated 10% Ordnance Gel with over 700 data points collected. Now the number of data points have climbed to over 800 with the same level of precision.

expanded72You will first need to read QAS which lays the foundation in terms of real-world physical science. It concisely describes the various parameters involved in the wounding mechanism. There is mathematical formulae, but don’t let that deter you. Everything is described in the easy to understand, Queen’s English. There is even simple to follow directions for building your own testing apparatus, and along with that you’ll need a chronograph and your test guns and ammo. You’ll need the velocity at impact and the recovered diameter and mass of the bullet. In my own simplified method, I chronograph 10 rounds 12′ from the muzzle to the center between the sky screens, then set the test medium 12′ from the muzzle. It really is that simple and the materials required for Chuck’s apparatus are all easily found. I also believe that he did an excellent job with each chapter being a building block to get a better understanding of the picture as a whole.

Once I had a handle on what was to be learned from reading QAS and being able to run the Q Model, I suggested that Chuck and Rob Behr should get acquainted. We have already begun giving results for various JHP bullet loads on the forum, mostly by Chuck and his eagerness to help us all. Rob has since read QAS and has the Q Model as well. I think I can speak for both us being duly impressed!

bullet catch72Now I’ll digress a bit in hopes that you will understand my point of view. Early on in reading QAS I began seeing the quantifiable similarities between water and 10% ordnance gelatin. Even a comparison of the speed of sound in both mediums being equal. I do calculations daily for things such as sound pressure levels and hydraulics and even some of the thermodynamic principles covered in QAS. To create an accurate reference work, the author must prove the soundness of his mathematical models, particularly as it relates to the physics of ballistics. So, you may ask how I could be largely in agreement with the author’s conclusions before having read his work? Obviously, experience doesn’t hurt. I’ve been shooting handguns for 40 years, long guns even longer. I’ve been handloading for 30 years now not even counting the prior years spent studying any handloading data I could get my hands on. My professional design experience is heavily laden with engineering mathematics that was a great asset when I began as a self-taught handloader. In short, the principles just made sense to me and considering the math necessary to make such predictions, I considered 95% accuracy about as good as anything I’ve seen in making predictions for bullet performance, regardless of whose predictive model we’re talking about. When it all culminated for me with the inclusion of energy and momentum, after reading QAS and talking with the author, I was elated. Not only can we predict terminal ballistic performance, we see that the nearly identical similarities between water and ballistic gel are proven mathematically.

115 silvertip72  And while I’m digressing, let’s go back to the event responsible for creating predictive models: the 1986 “Miami Shootout.” I had been shooting and studying terminal performance well before then. I still wonder to this day how the FBI would allow the use of the Winchester 115 grain SilverTip load in 9mm. At that time, 115 grain JHPs were commonly used in 9 x 19mm while 124 grain JHPs were beginning to see use by Law Enforcement. The 115 grain SilverTip didn’t distinguish itself in anything other than rapid expansion. At a rated 1200 FPS, muzzle energy wasn’t impressive at 368 Ft/lbs and momentum at .613 Lb-seconds. Not while there were two different 115 grain JHP loads they could have chosen that were labeled by the agencies using them: the “Secret Service” load made by Remington with a conventional 115 grain cup-and-core copper jacketed hollowpoint rated 1350 FPS and +P+. The other being the “Illinois State Police” load made by Winchester with the same spec’s that included their conventional 115 grain JHP. Both loads were closer to 1300 FPS from each agencies service pistols. Muzzle energy was improved to 432 Ft/lbs while momentum was better at .664 Lb-seconds at 1300 FPS. Both loads held in high regard by the agencies using them.

Another look from the top at the failed bullet's path.

Another look from the top at the failed bullet’s path.

Now let’s discuss ballistic hyperbole, first with the bleed-out theory as the only reliable wounding mechanism. You’ve probably seen me touch on this before if you’ve read any of my previous articles. One of the villains in this event was struck in the shoulder by a 115 grain SilverTip that went on to become lodged within 1” of his heart. Because of the rapid expansion from the softer jacketed hollowpoint, the load lacked the momentum to completely reach the heart yet was later determined to be a non-survivable wound. While the villain was waiting for bleed-out to occur he went right on shooting, wounding and killing! Would those additional 64 Ft/lbs of energy or .051 Lb-seconds of momentum have helped? Well, let’s consider that the copper alloy JHPs were easily better penetrators than the aluminum alloy SilverTip which makes the question fairly simple for me to answer.

147 subsonic72Instead, since the 1986 “Miami Shootout” until just recently, the FBI has been on the worn out treadmill of heavy for caliber subsonic loads. First with over-penetrating 147 grain JHP loads in 9 x 19mm at subsonic velocity. Other agencies followed the FBI’s lead until several incidents were reported with over-penetration being excessive enough that innocent bystanders were struck after the bullets had passed through the intended victim without great effect on the intended target due to the lack of expansion. Penetration is a very necessary component in the wounding mechanism, but if that was all there was to it we could all just carry FMJ ammo! We know better, so what does a JHP need in order to expand as it penetrates? Energy and momentum! Unfortunately, the 147 grain subsonic JHP loads were followed agency wide by the 10mm “LITE” which had a mediocre rating and subsonic velocity about like the 147 grain 9mm at around 975 FPS. There was also a firearm related failure issue that should not be overlooked, but again, the FBI had to revert to interim loads and pistols from the past. Neither should it be overlooked that when the 147 grain subsonic JHP loads in 9 x 19mm were failing, CorBon had found a solution: greater energy and momentum! At 975 FPS a 147 grain JHP has 310 Ft/lbs of muzzle energy with a momentum of .636 Lb-seconds, both inferior to the 115 grain +P+ loads. CorBon introduced a 147 grain +P JHP load rated 1125 FPS from a 4” test barrel that would yield 413 Ft/lbs with a momentum of .734 Lb-seconds. But the FBI was being led on another treadmill path by then with the 10mm “LITE” going ahead with mediocrity by selecting the 165 grain “Medium Velocity” (read subsonic) JHPs when they adopted the Glock pistols in .40 S&W. It was eventually upgraded with a 180 gr. JHP load. So, where is the FBI at today? A 124 grain +P JHP load in 9 x 19mm.

street stoppers72 In the early 1980s I used to buy a sort of “consumer reports” annual for handguns called Handgun Tests. The owner/publisher was a pretty colorful guy and like us, they acquired their test guns by buying them over the counter just like any ordinary citizen would do. They didn’t accept advertising from any gunmaker and they reported their findings just as we do today on the internet gun forums. One particular year they had acquired a report that had leaked from the FBI ranking various handgun defense loads. Not to anyone’s surprise, the .357 Magnum 125 grain  JHPs manufactured by Winchester and Federal were at the top of those rankings. Coincidentally, the ranking looked very similar to what we saw later with Marshall & Sanow’s Street Stopper books and periodical reports. Whatever you may think about OSS data, there were not mistakes made so great that a couple of honest working stiff cops should be vilified by their detractors. Particularly not from one so instrumental to the FBI subsonic treadmill and pundits who follow his lead even to the point of recommending a 300 grain XTP as the best choice for defense with a .44 Magnum.

stoppower72 One thing that Chuck illuminated for me was the research by others where the conclusions reinforce the findings of M & S. If I recall correctly, they did make it clear to everyone that they were not engineers, statisticians or physicists, nor should you only fire 1 round in a defense shooting. They simply reported events where it had been the case whether by departmental mandate, dumb luck, whatever. Myself, I appreciate the contributions they made while understanding the limitations. Ed Sanow did several articles where I believed that his conclusions were on the money. That was on the success rate with JHPs at or above 500 Ft/lbs of muzzle energy without going over 600 Ft/lbs running the risk that the bullet’s nose collapses rather than expands as has occurred with very powerful JHP loads in .41 & .44 Magnum where the bullet breezed through the target much like an FMJ. Even with the very high percentage numbers for incapacitation with 125 gr. JHP loads in .357 Magnum, some of them never penetrated deeper than 10”. Yet opposing pundits will tell you that energy as part of the wounding mechanism is meaningless as far as handgun loads, then try to convince you that the California Highway Patrol’s .40 Short & Weak as termed by J.D. Jones for the original Winchester 180 grain JHP load was just as, or more effective than 125 grain JHP loads in .357 Magnum with conclusions made from departmental shooting reports from the past where villains were shot multiple times. Maybe this is why the Texas Department of Public Safety didn’t need consultation from any of these “experts.” Replicating the proven performance of 125 grain JHPs fired from 4” service revolvers with an autoloading pistol and cartridge was the goal closest met by SIG/Sauer pistols in .357 SIG, ditto for the US Secret Service. Now with political correctness being more important than handgun cartridge effectiveness, some officers can’t master the 357 SIG and the DPS may at least have to provide some of them with 9 x 19mm pistols.

From left to right: .357 Sig, 10mm, .40 S&W.

From left to right: .357 Sig, 10mm, .40 S&W.

Not only have the pundits vilified Marshall & Sanow, they’re opposed to considering other research such as the Courtney’s (both Mr. & Mrs. hold a PhD in physics) ballistic pressure wave experiments. The thing is, these types of experiments have been going on for years where piezoelectric transducers have been implanted in dogs, whitetail deer, hogs and we know this was done during the Strasbourg Goat Tests that some believe never took place. I can tell you this: oscilloscopes don’t lie! Whatever the outcome, or any technology that can enhance our understanding of terminal ballistics is worth pursuing in my opinion, which takes me back to my own unscientific practices.

For many years I’ve been shooting water with one type of container or another. I’ve used wet newsprint both before and after the containers. While I knew the tests were not conclusive, I still felt that they were beneficial. Finally I just decided to shoot 1 gallon water filled milk jugs lined up in a row and established the standard for jugs penetrated with a 230 gr. JHP in .45 ACP. Regardless of caliber, that’s the standard my defense loads have to meet up to 4 jugs penetrated. Penetration through 4 jugs is too much and improvement must be made or the bullet relegated to practice.

jugs of water72One thing I’ve never understood is how any shooter could ignore the effects from various levels of energy using their own eyeballs, whether it be shooting water jugs or ballistic gel blocks, and particularly when viewing slow motion photography. Look at how the medium reacts because it will be different with varying levels of energy. Another point that I find loathsome is when pundits dismiss the importance of energy while rarely using loads that have very much of it. Skewing the test to achieve a desired result is meaningless, and don’t forget that momentum is a vital component in penetration. And, of course, energy is a vital component in momentum. In my opinion, it is momentum that these guys least understand and it does not equate solely to mass. The lighter the bullet is, the greater energy it will need to equal the momentum of a heavier bullet.

papershootoutmiami72 One theory of my own that I expressed to Chuck is a time measurement from impact to complete bullet expansion along with a linear measurement, combined with slow motion photography. While he has been very helpful in devaluing the significance of the temporary stretch cavity, he put me on the right path to something that accounts for energy and somewhat similar to my own theorizing. It comes from the incapacitation predictions where values increase with each successive shot, as they should while the value ∆E15 is the amount of energy expenditure from 1 – 15 centimeters. Oftentimes we see a greater area for the temporary stretch cavity with an increase in energy for a JHP viewing a gel block in slow motion as the bullet impacts and penetrates through the gel block. This is the only explanation I’ve agreed with to date.

As far as the incapacitation predictions, the criteria is simple in that the assailant is incapacitated within 30 seconds. Since we know that we should shoot at least twice before we assess, a number of good defense loads rate as high as 95% for the second shot. Penetration is essential so long as you don’t become obsessed with it. Energy and momentum are also essential and I like to have as much of both as is practical.

Kevin Newberry

Kevin Newberry