Barret .50

Barrett Firearms Manufacturing was founded by Ronnie Barrett for the sole purpose of building semi-automatic rifles chambered for the powerful12.7×99mm NATO (.50 BMG) ammunition, originally developed for and used inM2 Browning machine guns. Barrett began his work in the early 1980s and the first working rifles were available in 1982, hence the designation M82. Barrett designed every single part of the weapon personally and then went on to market the weapon and mass produce it out of his own pocket. He continued to develop his rifle through the 1980s, and developed the improved M82A1 rifle by 1986.

The first conventional military success was the sale of about 100 M82A1 rifles to the Swedish Army in 1989. Major success followed in 1990, when the United States armed forces purchased significant numbers of the M82A1 during operations Desert Shield and Desert Storm in Kuwait and Iraq. About 125 rifles were initially bought by the United States Marine Corps, and orders from the Army and Air Force soon followed. The M82A1 is known by the US military as the SASR—"Special Applications Scoped Rifle", and it was and still is used as an anti-materiel rifle and explosive ordnance disposal (EOD) tool. The long effective range, over 1,800 metres (5,900 ft) (1.1 miles), along with high energy and availability of highly effective ammunition such asAPI and Raufoss Mk 211, allows for effective operations against targets like radar cabins, trucks, parked aircraft and the like. The M82 can also be used to defeat human targets from standoff range or against targets behind cover.^{[citation needed]} However, anti-personnel use is not a major application for the M82 (or any other .50 BMG rifle, for that matter^{[citation needed]}). There is a widespread misconception that a number of treaties have banned use of the .50 BMG against human targets. However, the U.S. Army Judge Advocate General's office has issued a legal opinion that the .50 BMG and even the Raufoss Mk 211 round are legal for use against enemy personnel.^{[citation needed]}

Further development led to the M82A2 bullpup rifle in 1987, which was a reduced-recoil design to be fired from the shoulder. It failed to make an impression on the world firearms market, and was soon dropped from production. However, in 2006, Barrett completed development of the XM500, which has a bullpup configuration similar to the M82A2.

The latest derivative of the M82 family is the M82A1M rifle, adopted by U.S. Marine Corps as the M82A3 SASR and bought in large numbers. This rifle differs from M82A1 in that it has a full length Picatinny rail that allows a wide variety of scopes and sighting devices to be mounted on the rifle. Other changes are the addition of a rear monopod, slightly lightened mechanism, and detachable bipod and muzzle brake.

Another variant of the original weapon is the M82A1A Special Application Scoped Rifle, an almost identical model but specifically designed to fire the Raufoss Mk 211 Mod 0 round, a type of API (Armour Piercing Incendiary) ammunition.