What we too often don't recognize is that WE are incapable of reading each word of the constitution as the framers intended because language constantly drifts, the meanings of words constantly change. It's the nature of language.
As to assault weapons, it's probably 2A advocates who are indirectly responsible for the creation of that word. We spent plenty of time beating down anyone who used assault rifle inaccurately (I know I have), and thus assault weapon was born in the media to replace assault rifle, which we refused to let anyone use without pointing out their ignorance.
So there it is -- assault weapon -- and it means what it means -- it's a broader umbrella term, under which assault rifles fall, but also under which semi-automatic versions of assault rifles fall. There's nothing illegitimate about it. It's how language works, and every dictionary adds words and updates definitions as time goes on.
