It's like driving you know in about 30 seconds which morons you don't want to be on the road with when they are driving. Better yet, take the stupid people that operate watercraft, no training or licencing necessary. Neither one of these are constitutional rights. There are a lot more people killed by automobile/watercraft accidents verses pistols and long guns.
Evidence? Well I can tell in about 30 seconds at the range when someone has no idea how to use a firearm. You know, the folks you don't want to be in the range with when they're shooting? (: