Guns, Guns, Guns.

What exactly is the purpose of a gun except to kill? You have one around, somebody's gonna have an itchy trigger finger.
A couple of years ago, an American weekly ran a special with 365 pictures, each one representing a child killed during the previous year by someone using a gun. Mainly accidents (children playing with guns - found in a shoe box, in a closet, found under the bed, the sink, whatever).
When it's not the children, it's rival gangs, it's an unhappy co-worker, it's a couple of high-school students who've had it up to here. And it's not because you ban certain weapons or impose severe controls that they're going to disappear. Law-abiding citizens will play by the rules. Bandits, truants and anarchists couldn't care less about rules and will always find ways to get them.
Guns in the house. Nothing good ever comes out of that stuff.