The MAC-10 (Military Armament Corporation Model 10, officially the M10) is a highly compact, blowback-operated machine pistol developed by Gordon B. Ingram in 1964.
The M10 is a compact, select-fire, blowback-operated weapon, chambered for the .45 ACP cartridge. It is built predominantly from stamped steel. It has a 6-inch barrel, which is threaded to accept a suppressor. and fires from an open bolt. The bolt, like the Uzi, is of the telescoping design, which allows for a more compact weapon. Due to the light weight of the bolt, the MAC-10 has a very fast cyclic rate.
The telescoping bolt centers the mass of the weapon over the pistol grip, which is where the magazine well is located.
A notched charging handle protrudes from the top of the receiver; by turning the handle 90°, the bolt will lock, and act as an indicator that the weapon is unable to fire.
At the suggestion of the United States Army, Ingram added a small bracket with a small strap beneath the muzzle to aid in controlling recoil during fully-automatic fire.
The M-10 is part of a series of machine pistols, mostly in different calibers.
- The MAC-10/9 (chambered in 9mm but otherwise identical to the .45 ACP version)
- The MAC-11 / M-11A1, which is a scaled down version of the M-10 chambered in .380 ACP
- The M-11/9, which is a modified version of the M-11. It has a longer receiver and is chambered in 9x19mm. It was later manufactured by SWD (Sylvia and Wayne Daniel) and Leinad.
There were a few thousand semi-automatic pistols and carbines that were based on the original M-10 design. These were made in open bolt and later in closed bolt designs, in response to ATF rule changes that banned semi-auto open bolt designs, beginning in the early 1980s.
Masterpiece Arms manufactures a semi-automatic variant of the M-10 called the MPA-10. It differs from the original M-10 in firing from a closed bolt, as opposed to the open-bolt mechanism of the original M-10. This allows for more accuracy than open-bolt fire, and the extra cooling offered by open-bolt firing is unnecessary in a semi-automatic firearm. The MPA-10 comes in several versions, including a rifle-like variant with a 16" barrel, shoulder stock, and an AR-15 forearm. The stock model has 6" barrel (visually identical to the original MAC-10).
A highly modified version which has the charging handle on the side and has a scope mount on top is also available. One model has a 10" barrel and has an AR-15 style forearm.
Another variant that is growing in popularity for NFA registered firearms are the slow fire uppers manufactured by Lage Manufacturing which are called "MAX" uppers. The company is based in Chandler, Arizona. The "MAX" upper can reduce the original rate of fire to about 600 RPM (.45 ACP) and 700 RPM (9x19mm). The upper adds a picatinny optic rail, a side cocking charging handle, and a forend. Lage Manufacturing and Practical Solutions are currently marketing a drop-in 22LR upper variant that uses a modified upper, 22LR barrel, bolt and magazine. Besides Military Armament Corporation, MAC-10s and MAC-10 parts have been produced by RPB Industries, Cobray Company, Jersey Arms Works, MasterPiece Arms, and Section Five Firearms.