"Use enough gun" was and is the watchword of virtually everyone who hunts dangerous game. These folks want a gun that is chambered in a caliber that will stop dangerous animals right now—not just by & by—but right now! Having come nose to nose with some critters that could easily kill me, I never had any trouble understanding that admonition.
There was a time, in our not-too-distant past, when a man’s ammunition choices were somewhat limited. The old timers had the choice of using lead bullets, lead bullets or, for a change, lead bullets. Given the limitations of black powder, the only real way to increase power was to go to larger calibers and heavier bullets. There was very little discussion about expansion because there rarely was any expansion. This was the main reason that old time gunfighters wanted a handgun chambered in a caliber that started with a “4”.
Folks who are new to this business of defensive handguns may not realize what a great job our ammunition companies have done in fairly recent times. We now have jacketed hollow point bullets in most calibers that really will expand and penetrate in their intended target. And, for this reason, some of the less-than-starting-with-"4" calibers, like .38 Special & 9 mm, for example, can no longer be looked down upon with a knowingly, gunfighter shake of the head.
Still, it is a good idea to keep in mind that the defensive handgun may be called on to deal with problems that the armed citizen hasn’t yet thought about. That bullet that you are praying will stop the attacker may well have to get through glass, sheetrock or a car door, before it can do its job. Defensive shooters rarely practice shooting through such materials, but it is a good idea to remember that the fight is going to be what it’s going to be and these challenges may arise.
This is the reason that I still suggest that a person carry the most powerful handgun that he or she can shoot quickly and accurately. We simply don’t know what the challenge is going to be until we are face to face with it. And, just as when we are facing a charging cape buffalo, or a grizzly, we really want the attack to stop right now...in a few minutes really isn’t going to cut it.