The MAC-10 (Military Armament Corporation Model 10, officially the M-10) is a compact, blowback operated machine pistol developed by Gordon B. Ingram in 1964. It is chambered in either .45 ACP or 9mm. A two-stage suppressor by Sionics was designed for the MAC-10, which not only abated the noise created, but made it easier to control on full automatic (although it also made the gun far less compact and concealable).