Weapon Caliber: Base your decisions on fact, not fantasy
I published this piece on 1/12/19 on the American Warrior Society website. I am republishing it here, with their permission, in the hopes of widening the reach of the information it contains.
I was working at the FBI Academy’s Firearms Training Unit (FTU) when we made the decision to go to the 9mm round, as well as for a few years before and after. The FBI Ballistic Research Facility did the research and testing on the various rounds that led to this decision, with significant help from those of us in FTU.
We shot a lot of bullets in this process. And got paid to do it. Life was good. But I digress…
The bonded JHP 9mm ammo the FBI is now using is some very, very cool stuff. Internal and external ballistics are spot on, in that the rounds function very reliably in the duty weapons and are well within the consistent accuracy requirements of the Bureau. When it comes to terminal ballistics, the news is even better.
Weight retention on the rounds AVERAGED over 95%, even through common barrier materials. Given that the FBI is a national agency, it has to work in cities and out in the country, occasionally shooting through heavy winter clothes, car window glass, etc. We called it “barrier transparent”, because it just hammered through stuff and did not often peel or fall apart.
This meant that the bullets tended to impact with all their original bullet weight. When they hit their target, the bullets fully expand with boring regularity. This would give it a consistent permanent wound channel along its path every time. The Bureau wants 12”-18” of penetration, in order to ensure the rounds penetrate likely barriers, including clothes, as well as the targeted subject, to a point where vital structures are struck. As you know, subjects tend to move when bullets fly and end up getting hit at odd and oblique angels, not to mention coming equipped with a very wide range of body types and clothing. Penetration to a sufficient degree is important, while minimizing the risks inherent to overpenetration.
The permanent wound channels of handgun rounds in 9mm, .40 S&W and .45 ACP are so similar that it is nearly impossible for surgeons or medical examiners to tell the difference. A wider wound channel, of course, increases the chances of the bullet hitting something vital the subject’s continued misbehavior. Given that all of the commonly carried bullets now being in “serious handguns” can be counted on to produce appropriate and similar depths of penetration and nearly identical permanent wound channels, it really makes them a wash in this department.
I have been asked about “knockdown power” and hydraulic shock, citing hunting experience and anecdotal information from another shooter. Both are fairly common questions, in my experience, when it comes to self-defense handgun rounds.
Hydrostatic shock is an issue when firing rifle rounds, such as in the inevitable hunting scenarios people reference. Rifle rounds hit hard, compared to handguns, tending to launch heavier projectiles at much higher speeds. This can result is setting up a “wave” of force moving through impacted flesh, effectively creating a potentially devastating temporary wound channel that you do not see in handguns. The long and the short of it is, you are not going to benefit from this when it comes to your handgun’s terminal ballistics.
Knockdown power, often also referred to as “stopping power”, is a short hand term that became very popular a few decades ago during the seemingly never ending arguments between 9mm fans and .45 ACP fans. It’s a bit of a misnomer, in that nobody can really, accurately define it. To my mind, it is a term that muddies the conversation.
Example, if I shoot a person at 5 yards during his violent attack, hitting him with a grazing wound across his ribs with a .22 long rifle and he immediately falls down and quits his attack, is that a demonstration of the amazing stopping power of the .22? Or, if I shoot the same attacker at 5 yards directly through his heart with a .44 magnum, yet he goes on to fight effectively for another 2 minutes, does that demonstrate the terrible efficacy of the round? You can probably imagine a plethora of other similarly confusing scenarios without my input.
Social use of a firearm, particularly a handgun, is much too complex to fit into such simple buckets and many of the relevant factors cannot be controlled by the shooter. While you can control the weapon and caliber (within the bounds of local and federal law, of course) in the civilian world, you cannot control much else. What the subject’s wearing, what their mindset and determination are, what form of mind-altering substances they might be on are all factors in this rubric.
What you can control is shot placement and the speed of your follow up shot(s). If forced to use a firearm to defend yourself from death of serious bodily injury, you place the shots to the best of your ability in order to stop the threat. And as they say, if at first you don’t succeed…
Split times (the times between shots) on 9mm rounds are, generally, faster than with larger calibers. This means you can hit them multiple times in a shorter amount of time. You also, generally, have more rounds available between reloads in 9mm vs. larger caliber rounds in comparably sized handguns.
So, if the wound channels and penetration of the various rounds are similar, but one performs better in barrier material, recoils less and allows you more miles between fill-ups, the choice gets pretty clear pretty fast.
Unless you get all emotional about your favorite caliber. In which case, I wish you well.
