Where guns are allowed, rampage shootings don't happen.
In the case of guns, sure. But if a disturbed individual wants to go on a suicidal rampage and they have a weapon that will kill them and many others at once, why wouldn't they use it?
Are we back to nukes, then? Suicide bombers happen now, you know. (might want to ask yourself why they do that, too)
Not necessarily. Kevlar and something that spits out lots of lead all at once will also do the trick I imagine.