A Question of Caliber

To date, I have published three posts devoted to the selection of a personal defense handgun and how to gain proficiency therewith:

 What’s In Your Holster?                              March 20, 2014

 How Many Guns Do You Have?                    May 15, 2014

 Ask Somebody!                                         June 12, 2014

In this post, we are going to touch on ammunition choice, sort of.  You will understand my equivocation as you read.  The title of this week’s missive is a bit of a misnomer as ammunition preference is more closely tied to cartridge choice than caliber.  To understand why, I will need to get very basic for the non-shooter or novice.  You old hats can go get a beer now as nothing new will be offered here.  Come back next week when I promise, we’ll address that most interesting of subjects, my personal life.

What is caliber?  This is a very basic question easily answered.  Caliber is quite simply the diameter of the bullet and/or bore of the firearm.  It is measured either in millimeters (e.g. 9mm) or inches (e.g. .45 – note the decimal point).  Forty-five caliber handgun bore (that’s the hole running the length of the barrel) measures .45 inches, or a tad bit less than one-half inch.  Correspondingly, a nine millimeter bore and bullet measure just that; 9mm.  Get it? Caliber is no more or less than the diameter of the bullet.  But here is the twist, not all guns of the same caliber are compatible with all species of ammunition of the same caliber.

This is where the cartridge comes into play. So what is a cartridge?  A cartridge is the assembly of components that represent one round of ammunition.  They are: the projectile (bullet); the propellant (gun powder); the primer (impact ignition device, imbedded in the casing); and the casing (“brass” in the vernacular) which holds the entire assembly together and provides the explosion chamber when the gun is fired.  Pretty simple, huh?  A cartridge is generally identified by its caliber and the type of gun it was developed for, e.g. .45 ACP (Automatic Colt Pistol).

Any gun is earmarked (as well as physically labeled) to operate a specific cartridge.  The cartridge is very gun specific.  Let me give you an example. There are several cartridges available that contain a bullet measuring nine millimeters in diameter, among them; 9mm Luger, .380 ACP, .357 Magnum, .38 Special.  All of these use a bullet measuring 9mm in diameter (or .357 inches).  But they will not operate in the same firearms because each is fitted into a cartridge that is distinctly different in design.  That difference is reflected in the performance parameters (e.g. bullet velocity, muzzle energy) of each cartridge.

What are the differences in cartridges?  Well, the first is related to gun design.  The aforementioned .357 Magnum and .38 Special cartridges are designed for use in revolvers.  The 9mm Luger and .380 ACP are intended for semi-automatics (if you don’t know the difference, ask somebody).

The second difference is related to ammunition power.  The .357 Magnum is designed to be significantly more powerful than the .38 Special, therefore the cartridge of the Magnum is specifically designed to not fit in the chamber (firing hole, if you will) of the Special.  The same is true of the 9mm and .380 ACP.  This is a matter of safety.

The third difference is gun size.  The more powerful the cartridge in question, the heavier and larger the corresponding firearm must be.  Closely related to this is capacity of the firearm:  The bigger the cartridge, the fewer the number of rounds that can be practically carried.

If you are as smart as I think you are, you realize that up to this point I have made no recommendations about what caliber, or type of cartridge is best.  That debate has been going on since God was in diapers (by the way, who changed God’s diapers? … yeah, I know, I’m going to hell… but not for the reasons you think) and will continue long after I have shuffled off this mortal coil.  And if you have read my previous posts about firearms you have probably guessed that the answer is, “The best cartridge depends on the needs the individual shooter.”  You are so right!

A discussion about which cartridge in best will most assuredly generate passion among the participants.  But from what I have seen, read and learned on my own, everybody will bow to the maxim, shot placement outweighs power.  As there is no such thing as a (practical) one-shot-stop round, it is imperative that the shooter place the bullet, regardless of size or power, properly on target.  Accuracy equals efficiency.  Efficiency improves survivability.

And how do we ensure accuracy?  Practice!  So, the answer to the question, “Which cartridge should I use?” is; the cartridge you are most comfortable with as a shooter.  Because the only thing that will make you a confident shooter is your ability with the gun.  If you select a gun that is so powerful you won’t practice, that extra power is just wasted energy.

It is common in the defensive shooting universe to espouse a cartridge that achieves a minimum number of inches of penetration into a human body (saving your own life against a determined aggressor is a gruesome thing… get over your polite sensitivities).  There is some merit to this but still, the debate about which cartridge will do this most efficiently is fraught with variables and very much alive.  So what should you do?

I would recommend that a new shooter select the largest, most powerful cartridge they can confidently and comfortably manage (not tolerate… manage).  Your choice may be driven by recoil, gun weight, muzzle flash… there are dozens of things to consider, but the most important is that you own a gun you will shoot.  And shoot some more.   And even a little bit more.