By the way, I meant to add the following but it somehow got deleted when I posted my comment:

I think the only way the US solves its gun problem is to accept that reform is gradual, because gun culture is too embedded (the NRA etc and various older people who will never change their views). I think education is key, as is a gradual banning of things like assault weapons, accompanied by licencing, background checks, and training mandated at a federal level. Over time, I'd outlaw handguns too, so it is more akin to what we have in the UK (ie for the most part, you can only use them in gun clubs, where they are signed in and out, kept separate from ammunition, etc). This would take decades, but it needs to start somewhere, and crucially there needs to be the collective political will to make it start somewhere. Otherwise, this is just going to go on and on.

I daresay it will be unenforceable in certain areas, given the sheer size of the US, but that's another discussion.