UNITED STATES PROPERTY M 1911 A1 U.S.ARMY. Designed by John Browning. The original 1911 was adopted by the U.S. Army in May of 1911. In 1924 after several changes were adopted the pistol's designation was changed to the Model 1911 A1. The .45 ACP pistol served the U.S. Military through WWI, WWII, Korean and Vietnam until the M9 (Beretta 9mm) was adopted in 1985.