The police referred to it as an AR-15 assault-style rifle.
I've very briefly handled two assault style rifles in my life on different occasions, one was Australian Army issue (possibly an M16 variant), the other was an (illegal) Armalite (which was surprisingly light to handle). Even so, I'm sure like me, most people couldn't identify what was or wasn't classed as an assault rifle, especially when visually they have similarities.
