"Assault Rifle" had a perfectly acceptable and clearly defined meaning in the 80s. It was a rifle used by someone's military as a primary infantry weapon: M-16, AK-47 (and AKM, AK-74, etc.), HK G3, FN FAL, etc. Then we randomly decided the term meant any rifle that "looked dangerous." You people are all crazy. Get off my lawn.

Though I will say I've heard the media sometimes use the phrase "Assault Style Rifles" to refer to things like AR-15s, MAK-90s and HK 91's and though it rubbed me the wrong way, it was technically correct: it was a rifle styled to look like an assault rifle.