The M16 was converted from the rugged M3 by mounting quad M2HB 0.5 calibre machine guns in an electrically operated turret. The side panels had a hinged upper section with a centred notch to allow the guns to fire horizontally while the armour was still raised. A total of 2,877 M16 were produced between 1943 and 1944. The M16 served during the later stages of WWII and also during the Korean War for both air defence and infantry support.