Knight's Armament Company Masterkey

"Masterkey" redirects here and is not to be confused with Master key.

The Masterkey is a door breaching shotgun system manufactured by Knight's Armament Company.

Masterkey
Masterkey shotgun mounted on an M4A1 carbine
Type	Shotgun
Place of origin	United States
Specifications
Mass	2.6 kg (5.7 lb)
Length	43.2 cm (17.0 in)
Barrel length	25.4 cm (10.0 in)
Cartridge	12 gauge
Action	Pump action
Effective firing range	50 m (160 ft)
Feed system	3+1 rounds, internal tubular magazine

The Masterkey project was initiated during the 1980s to provide assault rifles with a potent built-in door breaching tool. Individual soldiers were often forced to carry a breaching shotgun in addition to their standard-issue rifle, but the Masterkey removes this need. The system consists of a shortened Remington 870 12 gauge pump-action intended to be mounted under a firearm's barrel, similarly to the M203 grenade launcher. It has a 3-round internal tubular magazine and can carry an additional round in the chamber, for a total of 4 rounds.

The shotgun can only be awkwardly operated independently because it has no grip behind the trigger—when firing the Masterkey, the rifle's magazine must be used as a makeshift pistol grip. Independent stocks and grips for the 870 are available for use, but they are incompatible with the M16 barrel mount. KAC makes an independent stock for the Masterkey that also can be used with the M203 grenade launcher.

The Masterkey inspired the M26 Modular Accessory Shotgun System, an attachable shotgun in use with the United States Army. The M26 was chosen by the Army over the Masterkey as a breaching tool.^[1]

The weapon is named "Masterkey" in reference to its ability to "unlock" virtually any standard lock.

Users

•  United States: Delta Force^[2]

See also

• Ciener Ultimate Over/Under
• Combat shotgun
• M26 MASS