Pilots are required to have a firearm and ammo as part of a survival kit in Alaska. We could carry anything we were comfortable with and big revolvers were generally preferred (you could break an arm in a forced landing, so shoulder weapons might be problematic) One guy I knew of carried a 20 gauge with slugs for "bear medicine" (though if a broken arm is a likelyhood, I hate to think of what would happen to a thin walled shotgun!) Pilots flying in from the lower 48 couldn't bring our handguns across Canada, so I flew with a 30-30 with 170 gr. soft points aboard.