Bah. It's just more hand-wringing and noise until the next one. The only practical solution is to outlaw new sales of semi-auto rifles and all handguns, including spare parts. Current owners would be able to keep what they have, but not be able to sell or devise them to next of kin.
IOW, nothing's going to change.
Even on liberal gun-owner forums I became quite unpopular yesterday for suggesting this after reading several posts claiming to want to "have a rational discussion" (or some other similar sentiment). My posts were downvoted out of existence and no small amount of personal insults hurled at me.
Liberals who own guns are, by and large, every bit as fanatical as conservatives on this issue. Their right to own nearly any type of gun they want outweighs your life and the life of your kids. They make the same idiotic arguments the right does, e.g., "Then why not outlaw cars too!"
In other words, this is an American gun-owner phenomenon, and no amount of data matters. For example, 3,000+ people died on 9/11 and we're still carrying on operations in Afghanistan and Iraq because of it. Since 9/11, well over 160,000 Americans have died from being shot by a someone with a gun, but we've done nothing. You'd think that kind of information would cause a good majority of these people to rethink their position, but it doesn't.
All this talk about mental health, background checks, etc., it's all bullshit. Crazy is a human thing. Armed and crazy is an American thing. And it's not going away.