Right after a prospective gunman decides which type of pistol to buy and carry, invariably, one of the things he asks is what caliber he should get. In fact, you would be hard-pressed to pick up any gun-related magazine and not see at least one article relating to ammunition and caliber choices.

Some instructors are also very caliber-focused, thinking that anyone who does not bring a .45 to class is unarmed. One student of mine who carries a 9mm was recently told that his 9mm was simply a 45 set on "stun." (However, the commentator declined to be stunned.) So what should you do when trying to decide on calibers/loads, etc.? In a previous article, we discussed the attribute of magazine capacity. Here, we will discuss the characteristics of each caliber and give you some information, so you can make up your own mind.

Issue Number One: Shootability

I had a student come to class with a Glock 29 in 10mm. My philosophy is that students should bring whatever they want to carry, and that was his choice. The only problem was that this gent weighed about 125 pounds and was arthritic in both wrists. To make matters worse, he brought 500 rounds of the heaviest, most powerful T-Rex stopping loads he could find in the caliber. To make a long story short, he ended up using my Glock 17 for the rest of the class. That caliber/weapon combination may have made a fine choice for a larger and stronger man, but for him it was totally unusable.

The caliber choice must be first predicated on the reality of your physical condition. Can you shoot the thing? Can you train with it? If you wince in pain every time you fire that dino-killer in training, you will never be able to use it well in a fight. Be honest with yourself. Let your intellect, and not your ego, select your caliber.

Issue Number Two: Delivery Envelope

Some students in my classes live and work in certain social circles where the pistol must not only be concealed, it must be covert. This means that weapon selection is as important as anything else. For them, an HK USP may be a fine weapon, but they will never carry it. Selecting a smaller weapon that will always be there may be a better choice.

There are small, large caliber weapons out there, but remember "Issue Number One." How shootable is it for you? My friend with the super-charged Glock 29 was trying unsuccessfully to kill both issues with one choice. If you must carry a smaller weapon, and shootability issues are present, do not feel impotent because you had to decrease caliber size.

Issue Number Three: Availability

We are seeing hurricanes, earthquakes, floods and landslides, and the memory of Katrina lies lightly on the minds of those who live in the Southeast. Natural disasters and riots can occur at any time. We are assuming that you will have your CCW pistol as a first line of defense until you can obtain something else. In the event that you cannot get to your survival stash, you may need to resupply from regular sources.

If you carry a .357 SIG, a .45 GAP, or any other new, non-mainstream caliber, do you think you will find the ammo you need? When I travel, I carry a Glock 17 in 9mm. Why? Because if my ammo does not arrive with my luggage (the illusion of security), I can always find 9mm. Perhaps this is not a huge issue, but it is still something for consideration.

Issue Number Four: Effects on Target

This is where all the bullet salesmen come out and discuss amateur terminal ballistics. Listen folks. Hundreds of thousands of people, both good guys and bad guys, have been killed with pistol shots in the last few decades. I will bet that the majority of those have been shot with 9mm. Why do I say that? Because I travel all over the world to teach good guys how to prevail in gunfights, and invariably the caliber of availability is 9mm.

"How on earth do they get past the fact that the 9mm is anemic and will bounce off of a leather jacket?" someone may ask. Truth be told, they shoot the bad guys until they either fall down or run away. Usually it is the former. It’s only here in the USA that we are so fixated on this issue of one or two shots.

We may hear all manner of arguments about one caliber or another being the only true choice, but I will tell you that no single caliber will be the best choice for everyone. Heck, some people are better served with a caliber like the 22 LR, due to physical limitations from advanced age or injury!

All calibers can fail and have failed. When you look at the issues scientifically, a 9mm or a .38 Special is approximately a .357; a .40 S&W is a 10mm; and a 45 ACP is an 11mm. So could it be that we have basically one or two little millimeters separating "T-Rex stopper" from "merely adequate" or "anemically inadequate"? Yes, that is exactly right.

Let me put it in a different perspective. A student of mine who works for a narcotics unit in the South recently reported in. He told me that he and his guys got in a gunfight with a violent drug dealer. Our student shot the bad guy once, using a shotgun loaded with Federal Tactical Slugs. (Incidentally, slugs are about .72 caliber and are suggested as anti-bear insurance in Alaska.) The shotgun slug entered the right side of the bad guy’s chest from about the 2:00 and exited through the back at about the 8:00.

Nice shot. However, the bad guy not only kept fighting, but stole a car and evaded the pursuing police officers, escaping into a wooded area. A week later, the bad guy’s attorney arranged for him to turn himself in. He was alive and well, albeit injured. Does anyone want to tell me how deadly their pistol round is now?

So select the size of your pistol first and foremost, and base it on what you need in order to carry it 24-7, 365 days a year (all the time). Select a caliber that is easily obtained and shootable for you. And finally, train to hit and keep hitting until the threat has gone away (one way or the other). A hit with a 9mm is far better than a marginal hit or a miss with a caliber that you cannot control.

Thanks to our friends at the United States Concealed Carry Association for this article. To get your free concealed carry newsletter click here.