The M16A1 is the Vietnam War era variant of the American M16 assault rifle, adopted by the US military in the late 1960s and known for its fully automatic fire. Its distinctive rapid report has been recreated in countless war films, shooters and military documentaries, which helped turn recordings of it into a stock gun sound online. On soundboards and in edits it is used less as a precise historical reference and more as a instantly recognisable shorthand for intense automatic gunfire.