MAC-10

The MAC-10 (Military Armament Corporation Model 10) is a highly compact, blowback operated, selective fire machine gun (technically, a machine pistol) developed by Gordon B. Ingram in 1964.

It is a simple, low-cost design with few moving parts, making it easy to manufacture and maintain. The M-10 is one out of a series of machine pistols, the others being: the MAC-11 (M-11A1), which is a scaled down version of the M-10 chambered in .380 ACP; and the M-11/9, which is a smaller 9mm version that has a longer receiver with a shorter profile later made by the SWD (Sylvia and Wayne Daniel) companies, Cobray and Leinad.

The compactness and high rates of fire for these weapons (no less than 1000 rpm for the M-10 and 1600 rpm for the M-11A1) worked against them. Their small size made them difficult to hold, and this, when combined with their high rate of fire (the magazine will empty in 1.57 seconds on full auto), made control challenging; this was a key factor in their never finding much success with the military. Also, their weight makes them uncomfortable to hold. However, they did see limited service in Vietnam with the Special Forces. They are still used today by some SWAT forces, the Brazilian Army's counter terrorist special forces and security outfits, as the high rate of fire (despite the difficulty of controlling the recoil) is useful in some situations.

Design
The MAC-10 was built almost entirely from steel stampings. A notched cocking handle protrudes from the top of the receiver, and by turning the handle 90° would lock the bolt, and act as an indicator that the weapon is unable to fire. The MAC-10 has a telescoping bolt, which wraps around the barrel. This allows a more compact weapon, and balances the weight of the weapon over the pistol grip where the magazine is located. The MAC-10 fires from an open bolt, and in addition, the light weight of the bolt results in a rapid rate of fire. The barrel is threaded to accept a suppressor, which worked by reducing the discharge's sound, without attempting to reduce the velocity of the bullet. 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.

Suppressor
Probably the biggest reason for the original MAC-10 finding recognition was its revolutionary sound suppressor designed by Mitchell Werbell III of Sionics. This suppressor had a two-stage design, with the first stage being larger than the second. This uniquely shaped suppressor gave the MAC-10 a very menacing look. It was also very quiet, to the point that the bolt could be heard over the report of the weapons discharge. Its "wipeless" design was advanced for the time in that its internal metal parts needed only to be cleaned, not replaced, in contrast to the older-technology "wipe" type suppressors. The suppressor also created a place to hold the weapon; this, combined with the weight it added, made the weapon easier to control. During the 1970s the United States of America placed restrictions on the exportation of suppressors, and a number of countries cancelled their orders of MAC-10s as the effectiveness of the MAC-10's suppressor was one of its main selling points. This and additional restrictions on automatic weapons in the USA led to the bankruptcy of Military Armament Company, the main producer, in 1976. The weapon's barrel threads were originally intended for this suppressor, but many other attachments are used: muzzle brakes, barrel extensions, fake-suppressors, fore-grips, and so on. Also, a single-stage "wipe" type suppressor was marketed by SWD and Cobray in the last years (1983-1986) of the MAC-10 SMG's manufacture.

Calibers
The MAC-10 is most common in the version chambered for .45 ACP rounds. In the United States, fully automatic MAC-10 machine pistols are NFA articles, and probably the least expensive (relative; Approximate cost as of Q1 2008 is $9,800 US +/-) and most common automatic firearms available on the American market today. A large amount of sheet metal frame flats were given serial numbers before the Firearm Owners Protection Act of 1986, and this made it possible to continue manufacturing MACs for the civilian market. There are also a limited number of semi-automatic carbines based on the original MAC design. MAC-10 pistols may be easily converted to carbines, and vice-versa, by interchanging commonly available parts. Originally Ingram made the MAC 10 into a .45 caliber. The first MAC 10 was designed and fabricated in Southern California by Erquiaga Arms in 1962.

Current military users
The current military users use MAC-10s primarily for counter-terrorist units, as its high rate of fire and relatively low power is ideal for hostage situations. Brazil is the only known export customer and currently uses it for special operation units.
 * Brazil
 * United States (no longer in general service but still used by counter terrorist units)

Video

 * Nazarian`s Gun`s Recognition Guide Mac 10 Silenced (.MPEG movie)
 * Video of Fully Automatic Mac-10 on YouTube