That's not a real definition. An assault rifle is a selective fire sub-caliber rifle.
It is in essence precisely the military definition of an assault rifle. Further, sub-calibre is a munition whose diameter is less that the bore such as is the case with a saboted round. I think you mean intermediate cartridge. But as I said, it's irrelevant how you categarize the weapon.
Guns do not cause school shootings.
What about: certain guns amplify the casualties in such 'postal events'? Surely even the most ardent firearms-admirer would concede this point in order to reserve any pretence of reason.
It's disgusting using kids deaths to disarm law abiding Americans...
Well when you (not you in particular or personally FPS) find the needless death of innocents
more disgusting and those irriplaceable lives more precious than your irrationally-worshipped weapons which go far beyond hunting or leisure or even (stretching it:) self-defence needs, then perhaps you would - paradoxically - demonstrate you are mature enough to have so many of them floating around.
...without doing anything to stop the actual problems of mental health issues and criminal violence.
You
cannot stop that. In fact presently you are unable to minimise its growth. Your culture celebrates force and idolises power as the go-to-solution for all problems. You have a uniquely selectively competitive society, set against inequality of opportunity and without what is considered in the rest of the developed world basic rights. Your groups are clustered by faction & not community. You are essentially locked into a civil cold war with little discord or communication just occassional shouting at each other. The forthcoming generation is unable to set a reasonable career course or an optimistic future because large conglomerates run amok with less regulation than royal houses of long-ago. Into this mix you throw FPS for 18-25-year olds, endless Hollywood fantasy movies, inadequate mental health care and the availability of actual weopons only dreamed about in the Great War: 400 rounds easily carried about your person limited only by your finger getting tired and you guys are perplexed why this keeps happening.