I would not use it in Big Bear country.
If a bear is coming at you and in handgun range shoot at Nostrils and mouth, not top of head. If it's not coming at you let it go away. Skull shots are not normaly at an acceptable angle and will ricochet off.
If he had time to reload a revolver (many shots in forehead) the bear was probably to far away when he first shot it. They move pretty fast. I might try one shot to turn it away but would try and hold the remainder till I could make good shots.
Get a 12 guage with slugs.