I carry a .45 Super ( 230 grain FP & 1200 fps handload ) when I go camping, and feel pretty safe against black bears and mountain lions. Since the 10mm and the .45 Super are very similar in terms of performance, I would feel pretty safe with a 10mm as well. Now if I was in Grizzly Bear country, I would want to carry a 12 gauge or some other rifle. The absolute best defense against a bear charge is to have a can of bear spray, and be prepared to roll up in a ball and play dead. Even better is just to avoid dangerous animals all together; it's not too difficult