But for any decent-sized animal, I think my .45 should work fairly well. The first round may not kill a bear-sized animal, but it should slow it down pretty well to allow me to squeeze off the other 20 rounds.
I might agree with you if we were talking about be attacked by a possum, but expecting a .45acp to be effective against a bear is foolish IMHO. I'd want at least a .45-70 rifle. And ten more friends with identical rifles firing at the same time.
As far as an animal attack, I've just never really worried about it. If that rare rare event ever happens to me, well, I guess I'm just dead then. It was my time. At least the buggers that killed me would be able to eat well for several weeks. Human predators scare me much more. Lightning scares me much more.
Well, we can verify easily that a .454 Casull revolver will in fact kill a charging bear with 2-3 accurately-placed shots.
http://www.thefirearmblog.com/blog/2009/08/31/man-kills-charging-bear-with-454-casull/I don't doubt that the .454 generates a lot more stopping power. But, I'd guess that firing 21 rounds of .45 would likely do some serious damage also.
But first off, we don't get a lot of bears where I live in Alabama. Second, I doubt I'd get to pick the time of a possible bear attack, so having ten friends with rifles around probably wouldn't be likely. And third, I'd have a hard time carrying a rifle around with me everywhere I go. But I do have a .45acp on me at all times.
So, I'll have to go with the .45 I actually have handy, versus the magical rifle I could produce from thin air.
Plus, I don't carry a .45 specifically to fend off attacking bears, I carry it to fend off attacking humans, dogs, whatever needs fending off.