Some folks are still missing the real point;
"Guns don't kill people, People kill people" This is the truth. Ever see a gun leap up off a table and shoot someone of it's own volition?
Substitute anything else that's ever proven lethal to human beings for 'Guns' -
Gasoline, fuel oil, fertilizer, cars, trucks, knives, axes, screwdrivers, hammers, lumber, rocks, water, pillowcases, plastic bags, balconies (as in pushed off of), windows (pushed out of), fire, prescription medicine, dynamite, bricks, broken broomsticks, sharpened toothbrushes, alcohol, and on and on and on... Oh, yeah...don't forget the bare hands you were born with.
Outlaw everything, destroy what you can't outlaw, and cut off everybody's hands at birth...and people will still try to kill each other, or have cause to 'snap' and go homicidal. They'd try to kick each other to death, for Cod's sake.
Trying to abolish guns would be just as successful as Prohibition was. The true, yet unaddressed, root cause of this kind of horror is people, and what pushes them to this state.
We'd be better off with sensible gun regulations, and a lot more time and effort looking at the most important part of the equation...PEOPLE.
I hope those poor kids and their families can pull through.