899th Antiaircaft Artillery AW Battalion (SP) (Source: Webmaster's collection) The inside of one of the battalion's M-16 multiple gun motor carriages at a range in southern Germany. The M-16 was based on the M-3 halftrack chassis that carried an M-45 Quadmount electric gun-turret which could rotate 360 degrees and was equipped with four M2 HB .50 caliber heavy machine guns. Crew of 5 (commander, driver, gunner and two loaders).