I don't hunt them, but know a guy that does, when I lived in AK I used to help him with his stands and even got to track a couple. He used a pistol twice, once by choice.
The one I was there for: just cleaning up at season end, bear decided to help so we went up the stand to let him, after a while he decided to check us out. To dissuade him took a 44Mag from a Blackhawk, loaded on the warm side I'm sure, not sure the bullet weight, could probably find out, it was a cast solid, not positive the profile something flat pointed. Distance: 6ft maybe less (that yell, stomp, make noise and they'll run stuff not so effective), hit square in the chest (memory fails me which organs were hit), fell off the tree, ran about 35yds just out of sight, thrashed about and moaned for what felt like an eternity but was probably less than 5 minutes. Boar, squared something like 6'8", not weighed, field dressed it was rough for the two of us to carry it and had the boat riding pretty low.
The one I wasn't: 45 Colt from a Blackhawk 250gr SWC, distance should've been less than 20yds, not sure where it hit, but the guy's no slouch, account of death, about the same.
Handguns suck. But if you want to go big, and practice a lot, I believe penetration matters more than expansion if there is a potential for large bears. Tracking one when you're not sure it's dead is unfun.