You have to get very ,very close to the bear to kill him with a 45. Now really... is that a good idea?
My friend did a 15,000 miler from Ohio to Fairbanks , Alaska and due to CCW restrictions carried a bic lighter and a can of some type of hair spray which he felt he could ignite into a flamethrower to ward off the bears. Now I personally think the Grizzley would grab both of off him and cook him with that stuff but my buddy is a 2 tour Nam Marine and I think I'd bet on him. BTW he did come back 45 days later with about 15,000 miles on his bike. What a summer that guy had!