I've seen a few people use handguns as bear deterenant (in addition to bear spray) for primary reason that rifles are hard to fire inside of tents.

Are they making wise decisions? Probably not, but .45 magnums apparently work for scaring bears away from tents.

Obviously people that live in cities are a different story as the police/troopers are far better equipped to handle wild animals and can legally discharge weapons within city limits without you needing to do paperwork or risking your life, just don't have food on you when backing away slowly.

edit: cars are also a reasonable deterrent (bears rarely try to attack moving vehicles, and when they do the driver is usually being stupid)

10mm, is the most common handgun round recommended for defense against bears, but .357mag, .44mag, .454 casull, etc, all work too if you're married to revolvers.