BB guns can barely break the skin.Someone would just run up to you and kick your ass.
Sure, you can run around with a heavy shotgun and ammo...Or you can carry a good old crowbar!
Mine is lethal if a pellet is launched and is to penetrate the neck and break a blood vessal.What about a frozen banana as a melee weapon?
BBs don't have enough velocity.
He could always beat them with the gun