In before the lock? <img src="/images/graemlins/smile.gif" alt="" />

Just offhand, I imagine your Mini-14 would be sufficient for the majority of your concerns. Obviously ammunition used can have a factor, but 5.56mm can be expected to penetrate deeper and do more damage than a .45. Looking at energies, a .45 might have ~350 ft lbs at the muzzle, and a 5.56mm will have somewhere around 1,400 ft lbs. There's just no comparing them.

There was a reply I heard one time when somebody asked what kind of pistol they should use to defend themselves from bear.... the reply went something like "it doesn't matter, just make sure you file down the front sight so it doesn't hurt so bad when the bear shoves it up your ***!" <img src="/images/graemlins/smile.gif" alt="" />

In all seriousness, if you are dead set on a pistol, I'd be looking into the high powered revolver range.