USAS-12

The USAS-12's history traces back to Maxwell Atchisson's designs in the 1980s. Around 1989, Gilbert Equipment Co. (USA) initiated the development of a selective fire weapon based on Atchisson's principles, with John Trevor, Jr. responsible for the design. Lacking in-house manufacturing capabilities, Gilbert Equipment Co. partnered with South Korean company Daewoo Precision Industries for production. Daewoo engineers adapted the weapon, commencing mass production in the early 1990s. The USAS-12 was subsequently sold to military and security forces in Asia, with over 30,000 units produced by the mid-1990s.

Simultaneously, Gilbert Equipment Co. attempted to introduce a semi-automatic version to the U.S. market, but it was classified as a "destructive device" under the U.S. National Firearms Act of 1934. In the late 1990s, RAMO Defence Co. assembled USAS-12 shotguns from Korean and U.S.-made parts for domestic government agency sales. The shotgun is still manufactured by S&T Daewoo (SNT Motiv) in Korea for military and law enforcement purposes. In 2007, Ameetec Arms LLC in the USA began manufacturing a semi-automatic clone, the WM-12, which was discontinued after a pre-production run.

The USAS-12 (Universal Sporting Automatic Shotgun 12 gauge) is a gas-operated, selective fire weapon chambered for 12 gauge shells, designed to provide sustained firepower in close-combat scenarios. It accepts detachable 10-round box magazines or 20-round drum magazines. Both magazine types are constructed from polymer, and the drum magazines feature a translucent polymer rear side. The USAS-12 has an effective range stated as 40 m. Its bolt locks using a single cylindrical locking piece.

A CQ model of the USAS-12 was created in the early 1990s, differing from the original model by the absence of a front sight and the presence of a re-modeled carry handle. Ameetec Arms LLC developed a semi-automatic clone designated WM-12 in 2007, which differed from the original USAS-12 in lacking fixed sights and a carrying handle, replaced by a Picatinny rail.

The USAS-12 has seen use in:

• the Mexican Drug War,

• the Karen Conflict,

• the New People's Army rebellion.

Users of the USAS-12 include state forces in Brazil (GRUMEC, army Special Forces battalions), Colombia (GAULA, COPES), Peru, South Korea (707th Special Mission Group), and Thailand. Private security forces in the Philippines also utilize the weapon. Non-state users include Grupos de autodefensa comunitaria, the Karen National Liberation Army, Los Zetas, and the New People's Army.