In America, it's the case that if guns are banned, then the bad guys will still have guns, but many good guys won't. So it's better to allow them.
In Britain(guns are banned and have always been banned), I hear of gun shots in the blackest areas. I'm not sure if legalizing them would reduce crime.
Guns would be useful to help defend ourselves against G-d forbid, a holocaust situation, a situation where our own govt, wants to wipe out jews.