Reminds me of the joke.
Guy was asked that question. He replied "First,never hike alone! For a gun just carry a .22 derringer. If charged by a bear, shoot your friend in his kneecap and briskly walk away. The bear will concentrate on him.
Seriously though, of the handguns I own, it would be my .45 (long) Colt. If I was to buy one, then a .454 casull
LEO, NRA member, Native Texan. Shooting and hunting for over 45 years!