I think a lot of people are confused by stopping power and lethality. I see a lot of people who seem to use them interchangably.
Almost any size round can be lethal if used right. As someone else posted, the AR-15 (an excellent gun) uses a .223 round and it is a highly lethal weapon. However, if you shoot someone with a .22 short round from a short barrel pistol, well you might as well beat them over the head with the pistol. It will probably be more effective.
A bigger round, like a .44 magnum, a .45 ACP, or a .50 caliber will almost always stop someone dead in their tracks. A smaller, high velocity round like a 9mm can go straight through someone without them even realizing they've been shot (for a while anyway).
But I also subscribe to the school of thought that says I'd rather carry a .25 than nothing at all.
However, if you shoot someone with a .22 short round from a short barrel pistol, well you might as well beat them over the head with the pistol. It will probably be more effective. The Israeli El Al airline security officers assigned to that detail by the General Security Services [ShinBet] thought otherwise, and found the reduced loads used in their .22 Berettas [loaded in .22 long rifle cartridge cases for feeding through the pistols magazines, but at .22 short velocity levels] were quite okay. I had the chance to shoot with a couple of those operators, who thought that shooting off a 500-round box of ammo was a good warmup, and that my Browning GP was unnecessarily noisy. A few also used the .22 short chambered Astra model 2000 *cub* as a backup handgun; the little Astra makes even a Walther PPK look large by comparison; I used to keep one as a backup in my handcuff case. But again, you have to practice with it to get the desired result.
There's at least one recorded case of an elephant being killed by a .22 short. And do not ever think that if such a weapon is pointed your way that your life is not in danger.
