I live in black bear country and have spoken to Fish and Game officers who also hunt. They all recommend not to shoot a bear with a handgun but carrying a shotgun may not be possible. They recommended a minimum of a hot-loaded hard cast SWC in .44 Magnum. If limited to a .357 Magnum (they now carry Glock 22's) they would use the same type platform, i.e. heavy hard cast SWC at the highest velocity you can find. Buffalo Bore ammo comes instantly to mind; Federal also makes similar hunting loads. Shoot for the face since the orbits (eye sockets), the nose, and the mouth are relatively soft targets. Shooting the chest/torso is a waste of time since bears have a built-in bulletproof vest on. A moving bear makes a challenging target. Practice-practice-practice! Good luck.