Gordon B. Ingram, an American arms designer who previously developed several submachine guns under his own name (such as Ingram Model 6), began work on a more compact submachine gun, suitable for clandestine operations, in around 1964. Several prototypes were made by Ingram by 1965, and in 1966 at least one prototype gun was purchased by US Army for test and evaluation. In around 1969 Ingram joined the Sionics Co, which previously manufactured silencers for small arms, and company started tooling up to produce Ingram submachine guns. In 1970 the Sionics was incorporated into larger company Military Armament Corporation (or MAC in short), located in Powder Springs, GA, USA. The same year MAC company commenced production of two versions of Ingram submachine guns - the larger Model 10 (M10), chambered for 9x19 or .45ACP ammunition, and smaller Model 11 (M11), chambered for 9x17 (9mm Short or .380ACP). Either version was available with silencers, developed by Sionics / MAC. The MAC ceased its functioning in 1976, and manufacturing rights for Ingram M10 and M11 submachine guns were transferred to RPB Industries Inc, located in Atlanta, CA. later on, submachine guns and semi-automatic only "pistols" and carbines, based on Ingram design, were manufactured by several more companies, such as SWD Inc, Cobray, and others. Copies of M10 were manufactured in Taiwan and Japan. Original weapons were sold to Chile and Yugoslavia during early 1970s; later on, sales were made to some Asian and South American countries.
Ingram M10 in 9x19mm caliber, as made by MAC, with stock retracted.
Ingram Model 10 and Model 11 submachine guns were intended for close encounters and for concealed carry. Several versions of M10 were made with longer barrels, including rare "carbine" version with barrel being about 450mm (18") long, and partially enclosed into perforated barrel jacket. The "civilian" clones of Ingram models were made in a great variety of modifications, with minor differences in almost every detail. Cobray 9mm M11 "pistols", for example, were based on experimental submachine guns developed at RPB Indusries in around 1979; these guns had longer receivers necessary to increase the bolt travel and thus decrease the rate of fire; in semi-automatic versions this feature is, obviously, irrelevant.
Ingram M10 in .45ACP caliber, as made by MAC, with stock extended.
Ingram Model 10 is blowback-operated, selective-fire submachine gun, that fires from open bolt. The bolt has firing pin milled in its body (or pinned to it). Bolt is of telescoped design, with most of its weight located in front of the breech face, around the barrel. Cocking handle is located at the top of the gun, and can be used to lock the bolt in forward position, when handle is turned sideways by 90 degrees. The receiver is made from formed sheet steel and consist of two parts - upper and lower. Receiver parts are connected by steel pin at the front of the weapon. Charging handle is located at the top of the receiver and doesn't move with the bolt when firing. The muzzle of the barrel is threaded to accept silencer. Controls include a manual safety, made in the form of a slider located inside the trigger guard, and a separate fire mode selector, made in form of a rotary lever located on left side of weapon, above the front of trigger guard. The shoulder stock was of telescoped design with folding shoulder rest made of steel wire. To provide additional stability, a leather loop attached to the front of the receiver, which is used to hold the gun by non-firing hand.
Ingram M11 in 9mm Short (9x17, .380ACP) caliber, as made by RPB Industries, with 16-round magazine.
Sights are mostly simple types, and include non-adjustable diopter type rear and protected front blade.
Ingram M11 in 9mm Short, with installed silencer.
Ingram M10 in "carbine version" with extended barrel and modified shoulder stock.
Cobray M11 "pistol" in 9x19mm - one of semi-automatic clones made to Ingram M10 pattern; note longer receiver and lack of fire mode selector switch.
| Ingram M10 | Ingram M11 | |
| Caliber | .45ACP and 9x19 Luger | 9x17 Browning Short (.380ACP) |
| Weight | 2,84 kg empty | 1,59 kg empty |
| Length | 269 / 548 mm | 222 / 460 mm |
| Barrel length | 146 mm | 129 mm |
| Rate of fire | 1145 (.45) / 1090 (9mm) rounds per minute | 1200 rounds per minute |
| Magazine capacity | 30 (.45) or 32 (9mm) rounds | 16 or 32 rounds |
| Effective range | 50-70 meters | 30-50 meters |
