You are right, I lumped assault weapons with the “other fringe” weapons because of size alone. The elephant in the room is Handguns – three times the deaths as rifles and assault weapons. A shooter with a 10 round magazine handgun (not high capacity) can do a lot of damage – with a mag change a lot more.
And even if we could outlaw all assault weapons, I don’t think it would save lives, only change the choice of murder weapon.
And yes I see mental health as a problem. We used to do a much better job of managing the lunatic fringe. But since the early 70’s, mental health has been losing funding and managed by incarceration rather than treatment. More money might help give options to patients and their families, but avoiding the next homicidal rage – I doubt it. Even if 4.3 million walking “psychotic” is over estimated by a factor of 10, it still leaves 430 thousand possible rampage killers walking around waiting to make themselves famous. If its societal pressure driving these horrors, we are lucky that we only see 1 of our 311,000,000 citizens going homicidal per year
And if the rumored connection between psychotropics (Prozac, Zoloft, et. al.) and murder/suicide is real, more access to mental health facilities and prescription treatment might raise the number of murderous rampages. The only comfort I can take is that statistically the chances of being the victim of one of these horrors is 1 in hundred thousand range.