Best semi-auto pistol to handle 45 ACP hollow points?

Nothing less than a 44 mag for the grizzly, independent of your scenario. I believe that it is the minimum size handgun that you stand a good job of disabling the bear with a single shot. A 45 just won't have the penetration.

The 44 mag has almost twice the energy as the .45 acp, providing enough energy to penetrate to the heart/lungs. A 45 acp will stop a 300 lb man, so it would probably be sufficient for a a 300 lb bear. In that case the number of rounds and faster follow-up in a 45 auto (as many as 15 plus spare mags) might be the advantage.

Also, concerning your scenario, in a bear attack I would be surprised if you had enough time to recognize the threat; draw you handgun; and get off all six shots in a revolver before he was on you.

Whichever bear I might encounter, I'll rely on a .44 Mag revolver, not a .45 ACP semi-auto pistol. I don't miss with my first shot, let alone my first three. Bears are big animals, so you'd have to be a very bad shot to miss one at close range.

For black bear, I carry a Smith & Wesson .44 Mag revolver, and for grizzlies, I'd carry a S&W .500 revolver. One powerful bullet beats several of much less power.

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