I guess I don't see how the gun matters. It's the goofs that do terrible things with them. If you ban those automatic or semi auto weapons then the law abiders will not have one and the law breakers will find a way to get one. What changes?
30 round clips vs 10 round clips, when you chose to shoot at unarmed targets it don't matter, just carry more clips. So it's not the guns, it's the goons using them.