the thing about more gun control is that it would prevent a ton of deaths in the aggregate, but these ultra-determined, mostly white or high-performing minority shooters with money would almost certainly get hold of guns anyways, so spree killings aren't necessarily the best example of preventable gun violence
that doesn't mean that the effect wouldn't be positive overall though, and I don't see how much harm can come from immediately a) bringing back the ban on assault weapons and b) closing the gun show loophole