But one year the UK had zero
firearm homicides back when everyone there carried guns. Now it's one of the most violent countries in Europe.
One of the problems is that virtually no gun law would've prevented the Newton massacre because the mother owned the guns that were used, and she wasn't on anyone's radar. You could try banning guns, but the cities that did that are always vying with each other as murder capitals. The massacre in Newton would be a good week for Chicago, Washington, or New York, where guns are banned. In contrast, most US towns that have guns coming out of their ears have a lower
murder rate than the UK.
When a psychotic killer is targeting first graders he could use a hammer and do just as well, perhaps better because a hammer wouldn't have alerted the whole school, but more likely they'd just do more planning and preparation, like the theater shooter in Colorado who was making bombs and booby traps.
More productive responses would be for schools to assume that they will
be targeted by a psychotic killer under any scenario of gun contol, since SWAT team members have mentally unstable relatives as often as other families do, and go from there. Why can't the principal's office have a panic button that locks all the classroom doors so nobody can get into them? Why not make sure those doors can stand up to some severe assaults? Why not take some basic disaster mitigation steps, because the last gun in town is almost guaranteed to be the one in the hands of the nutcase.