[Byte1]

Personally, if I was going to ANY enclosed structure where there was groups/crowds that I intended to shoot, I would find a semi-automatic such as a Glock 9mm (example) with a 30 round magazine. Actually, I would choose two of them. Pistols are more effective in close quarters, as far as I am concerned. But, real AR-15's are sometimes used today because they are used in video games and by those in combat. Actually, many rifles used in mass murders are actually, similar to AR-15's, not the actual AR-15s. But, most civilians do not know the difference between a revolver and a semiautomatic pistol, let alone the differences in semiautomatic rifles. It won't matter if they take away the AR-15. It will just be replaced as a preference with something else equally as lethal.
Like I said before and again and again, to protect the children you must harden the physical security. Until you take that seriously, it will all be about ridding the decent folks of their big bad bang, bang guns.