A long time friend stopped a really pissed of Brown Sow, with a 10mm Glock..
just a few months ago, south side of Kachemak bay. Just dropping the bear, he tripped, fell backward, and sent the last round of 10mm through his foot. Might have been 6 or 7 hour skiff ride back to town, he's a tough bastard.
IF the .45 Win Mag is a particularly reliable example, you'll have a chance.
Myself, I'd rather have a real short 12 gauge.