I just skimmed through what Perseus wrote, I don't disagree with it. Anything brutal, including affects on their family (like North Korea) would actually work, but there's no real good solutions for open-free country like U.S.
Some of you're saying the problem are people themselves. while it is true, their easy access to the guns are the actual problem. every one of us have some way or the other have issues. you can't ever satisfy us all, that's why we're going after the weapon first.