How a Barrett M107 works

The XM107 was originally intended to be a bolt-action sniper rifle, and the rifle Barrett M95 was originally selected by the U.S. Army in a competition between such weapons. However, under the trials, the decision was made that the U.S. Army did not, in fact, require such a weapon.

Then the Army decided on the Barrett M82, a semi-automatic rifle. In summer 2002, the M82 finally emerged from its Army trial phase and was approved for "full materiel release", meaning it was officially adopted as the Long Range Sniper Rifle, Caliber .50, M107. The M107 uses a Leupold 4.5–14×50 Mark 4 scope.
Overwatch being provided by an army sergeant during a high-level meeting in Baghdad

The Barrett M107 is a .50 caliber, shoulder-fired, semi-automatic sniper rifle. Like its predecessors, the rifle is said to have manageable recoil for a weapon of its size owing to the barrel assembly that itself absorbs force, moving inward toward the receiver against large springs with every shot. Additionally, the weapon's weight and large muzzle brake also assist in recoil reduction. Various changes were made to the original M82A1 to create the M107, with new features such as a lengthened accessory rail, rear grip, and monopod socket. Barrett has recently been asked to develop a lightweight version of the M107 under the Anti-Materiel Sniper Rifle Congressional Program, and has already come up with a scheme to build important component parts such as the receiver frame and muzzle brake out of lighter-weight materials.

The Barrett M107, like previous members of the M82 line, is also referred to as the Barrett "Light Fifty". The designation has in many instances supplanted earlier ones, with the M107 being voted one of 2005's top 10 military inventions by the U.S. Army