If I were going to be around charging brown bears the most useful handgun I can think of would be a Desert Eagle in 50 caliber, backed up by a large caliber rifle and a couple of friends with large caliber rifles as well. Better yet, I really like to avoid situations where I might encounter charging 800# bears!
OTOH, any of the original magnum cartridges from 357 to 41 to 44 would be likely to work for “normal” encounters. In fact, even the 327 FM mentioned earlier would take care of about 95% of the situations I would be likely to encounter, but of course YMMV!
Froggie