The USAS-12 is a gas-operated, select-fire weapon which is designed to provide sustained firepower in close quarter combat scenarios. It accepts detachable 10-round box magazines or 20-round drum magazines. Both types of magazine are made of polymer, and drum magazines have their rear side made from translucent polymer for quick determination of the number of shot shells left. It has an effective range of 40 m.
The gun was originally designed during the late 1980s in the U.S., by Gilbert Equipment Co. However, no domestic companies were interested in buying and producing the shotgun, and the only company that showed real interest was Daewoo Precision Industries of South Korea. Mass production started in the early 1990s, becoming very popular in Asia, with 30,000 built by the mid 1990s.
During this time period, attempts were made to import the shotgun to the U.S. market in a semi-automatic only form. However, the gun was blocked from importation due to its military background. Instead, a few companies built very limited numbers of them in the U.S. to bypass import restrictions. In 1994, the USAS-12, along with the somewhat similar Armsel Striker, were declared Destructive Devices, and had to be taxed and registered with the U.S. federal government. Although some are still made on a very limited basis for civilian in the U.S., they are heavily restricted to due their classification.