On March 4, 1963, the Department of Defense's Advanced Research Projects Agency made the first purchase of the Stoner 63, ordering 25 units in various configurations. In August and September 1963, the Stoner 63 was sent to the Marines Corps Landing Force Development Center at Quantico for evaluation, where it made a positive impression with its light weight and high ammunition capacity; the Marines favored the rifle and light machine gun configurations. Trials were performed by the Army Materiel Command (responsible for logistical support for the Marine Corps) at their own test facilities.