The Ingram Model 10, better known as the MAC10, named after its producer Military Armament Corporation, is an American open bolt submachine gun designed by Gordon Ingram in 1965. In 1970, the company Ingram worked for, Sionics Inc, was merged into the larger Military Armament Corporation, and there MAC10 was put into production. The 9x19mm and .45 ACP versions were introduced simultaneously. The .380 ACP version was introduced later in the same year. The MAC10 was then offered to the U.S. Military during the final years of the Vietnam War as a weapon for special operations and for support personnel, like armored units (hoping to replace the M3A1 "Grease Gun" Submachine gun as the self defense weapon of most tank crews).

The MAC10 didn't generate a lot of interest from the U.S. Military due to its small size and high rate of fire (too high it turns out for most operational uses). The lack of a foregrip motivated M.A.C. to provide a grip strap in front so that a second hand could hold down the gun and control the extreme muzzle climb when firing a long burst. But it was still an awkward weapon to fire and was most popular when mated with the efficient Sionics Two Stage Sound Suppressor. The Sionics Suppressor increased the length, quieted the sound (in a manner that was impressive for its day), and gave the shooter a stable point to grab with the second hand.

CIA and SEAL units used the MAC10 in Vietnam, and Special Ops units from other countries (Israel, UK and West Germany to name a few) have been seen wielding versions of the MAC10 during that time period. Unfortunately no major military ever formally adopted the weapon and it was sold mostly to elite police units (foreign and domestic) as well as special covert ops units until Military Armament Corporation went bankrupt in 1976. The death knell was the U.S. Government ban on selling Silencers/Suppressors to other countries (a ban that has since been lifted). As foreign clients only wanted the MAC10 with the Sionics Suppressor, orders fell to nothing. Ingram MAC10s can still be seen in South and Central America (usually 'gifts' from the CIA over the years) and in the armories of some European countries, but no one uses it as a 'front line' weapon any more.

Other companies then built transferable versions of the MAC10/9, MAC10/45 and MAC11 : most notably RPB Industries and SWD Corporation. Only the MAC guns built by M.A.C. (when Gordon Ingram was there) can be called "Ingram MAC10s". It is worth noting that this is not official nomenclature (Military Armament Corporation only ever called them the M10 and M11) but since it is so frequently used by dealers, collectors and firearms authorities, it has become more or less the generally accepted name for these guns.