M21

The M21 Sniper Weapon System (SWS) is the semi-automatic sniper rifle adaptation of the M14 rifle. It is chambered for the 7.62×51mm NATO cartridge. The United States Army wanted an accurate sniper rifle during the Vietnam War. The M14 was selected because of its accuracy, reliability, and the ability for a quick follow up shot. As a result, in 1969, the Rock Island Arsenal converted 1,435 National Match (target grade) M14s by adding a Redfield ART Adjustable Ranging Telescope 3–9× and providing National Match grade ammunition (7.62 Lake City Long Range XM-118). This version, called the XM21, had a specially selected walnut stock and was first fielded in the second half of 1969. An improved version with a fiberglass stock was designated the M21 in 1975. The M21 remained the Army's primary sniper rifle until 1988, when it was replaced by the M24 Sniper Weapon System; some M21s were later re-issued and used in the Iraq War. In standard military use, the M21 uses a 20-round box magazine as the other members of the M14 family and weighs 11 pounds (5.27 kg) without the scope. The U.S. military never officially authorized or purchased magazines in any other capacity, although 5- and 10-round magazines are available.