Self defense, stopping power, and caliber: Part 1 of a series.

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I’ve gotten a bunch of emails recently regarding the choice of an appropriate self-defense handgun caliber and/or bullet. Around this one topic swirls more misinformation – and outright inanity – than any other I can think of. And now, here’s mine!

What follows is a layman’s understanding, backed by research of available literature and years of hunting and shooting experience, of the practical mechanics of wound ballistics. It is not intended to be a complete and exhaustive study of the subject. Instead, I hope to give my readers – who are, in all likelihood, laypersons themselves – a solid base of information to help make good decisions when choosing self defense ammunition.

Let’s start by understanding that in a self-defense scenario our goal is simply to cause the perpetrator of a crime to cease immediately his/her antisocial activities. That’s it – we want the miscreant to quit doing whatever it was that caused us to draw our gun in the first place. The closer to “immediately” that this occurs, the better for all concerned.

There are two mechanisms by which this can be accomplished: psychological incapacitation and physical incapacitation.

The first – psychological incapacitation – is the least predictable of the two. Some people will stop and run when grazed by a well-thrown rock, others will soak up all manner of chemical, electrical, and physical deterrents without so much as flinching. Since it’s all in the mind, and minds vary significantly (especially when intoxicated in some form), we cannot count on delivering a reliable jolt to a criminal’s psyche. We must instead focus on doing enough physical damage to cause cessation of action through reduction of motor skills.

On this subject has been constructed all manner of measures, each attempting to quantify the unquantifiable: “One shot stops.” “Knockout index.” “Wound channel volume.” There are more, and none of them ever seem to agree (at least most of the time) on what actually works.

Well, folks, hunters have known something for a very long time, and it has been proven in the field again and again: to reliably put the brakes on a living entity, a bullet must do what I call The Twin Tasks.

1) It has to get to something the body finds immediately important, and
2) It has to do rapid and significant damage to that thing when it arrives.

That’s it. Either, by itself, simply won’t deliver the results we seek (at least, not in the physical sense.) If the projectile fails at either of these tasks, any success that occurs is in fact a product of psychological incapacitation, which we already know to be both unpredictable and unreliable.

Keep in mind that as the bullet traverses the target, it may repeat the Tasks; in other words, it may encounter more than one thing the body finds important. The more times that it does, and then completes the second Task, the faster the incapacitation is likely to occur. (Note that I didn’t say “will”, only “likely to”. Handgun rounds are underpowered things, and with them nothing is ever certain.)

Within certain limits, it doesn’t really matter what the caliber is or what the bullet is made of or how fast it travels, as long as it does both of the Tasks. That’s why there seems to be such a wide range of calibers, weights and velocities that have shown “good” results in self defense shootings, and why arguments about “stopping power” rage on the gun forums: there is, as the saying goes, more than one way to skin a cat.

Remember, as long as both Tasks are accomplished, the envelope of “how” they are is large enough to encompass a variety of approaches.

The reason that the “heavy and slow” and “light and fast” bullet camps exist is because, generally, their choices just happen do both of those Tasks on a fairly regular basis. Arguing about which is the “better” approach is really quite silly, because when they work it’s because they did both Tasks, regardless of the actual mechanism; when they fail, it is simply because they didn’t do one (or both) of the Tasks, again regardless of their physical attributes.

It’s at this point that someone invariably chimes in “but my cousin is engaged to a girl whose brother-in-law heard about a guy who saw someone shot fifteen times with a 9mm, and the victim was still able to walk into a French restaurant, order a 5-course meal, eat, chat with the sommelier, and stiff the waiter before finally collapsing on the sidewalk while waiting for his cab! That’s why I carry a .467 Loudenboomer Ultra Grande – if it hits them in the pinky the hydrostatic shock wave will knock them down!”

I’m exaggerating, you understand, but if you regularly haunt the gun forums you’ll recognize that it isn’t all that far off.

Yes, small caliber bullets fail. Guess what? Large caliber bullets fail, too. As someone once told me, “put on your big-boy pants and deal with it!” Don’t believe me? A good friend once gave me a first-hand account of a battle incident wherein a fellow absorbed several torso hits and was still able to jump from his vehicle and cross a road before finally collapsing in the ditch.

The gun in question? A .50 caliber heavy machine gun. Yes, you read that correctly. Sometimes, folks, nothing works.

Our job is to choose those calibers and bullets which seem to do the Two Tasks fairly reliably, and prepare to deal with the times that it just isn’t enough. With handgun rounds, those times are more common than the gunshop commandoes would have you believe.

In the next installment, we’ll take a layman’s look at the physics involved.

(To read the other installments, just click on the “Stopping Power” tag!)

-=[ Grant ]=-


About the Author:

Grant Cunningham is a renowned author and teacher in the fields of self defense, defensive shooting education and personal safety. He’s written several popular books on handguns and defensive shooting, including "The Book of the Revolver", "Shooter’s Guide To Handguns", "Defensive Revolver Fundamentals", "Defensive Pistol Fundamentals", and "Practice Strategies for Defensive Shooting" (Fall 2015.) Grant has also written articles on shooting, self defense, training and teaching for many magazines and shooting websites, including Concealed Carry Magazine, Gun Digest Magazine, the Association of Defensive Shooting Instructors ADSI) and the popular Personal Defense Network training website. He’s produced a DVD in the National Rifle Association’s Personal Firearm Defense series titled "Defensive Revolver Fundamentals" and teaches defensive shooting and personal safety courses all over the United States.
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