The Barrett XM109 Anti-Materiel Payload Weapon (AMPR), formerly known as the Objective Sniper Weapon (OSW), is a prototype semi-automatic anti-materiel rifle developed by Barrett Firearms Manufacturing.
Prototypes of the weapon were created in 2002, with at least 10 prototypes known to exist as of 2004. The XM109 and the XM500 anti-materiel rifle were both merged into the Anti-Materiel Rifle Congressional Program in 2006. The status of the weapon is not entirely clear; there have been no claims of it being either adopted or canceled.
The weapon uses a short-recoil system similar to the Barrett M82A1 which it is based on. The top receiver of the XM109 can be put on the lower part of the M82A1's receiver to form a fully-functional XM109 rifle.
It also features Barrett's BORS (Barrett Optical Ranging System) ballistics computer, along with a MIL-STD-1913 Picatinny rail, a monopod socket, dual-chamber detachable muzzle brake or suppressor, and a detachable bipod and carrying handle.
Its barrel is 17.6 inches, shorter in comparison to the M107's 20 or 29 inch barrel. It uses a 5-round magazine.
The weapon showed an increased effectiveness against various targets, but the recoil was beyond human limitations. Because of the high recoil, Barrett is researching a recoil reduction system for the XM109.
The XM109 uses the same 25×59mm grenades as used in the crew-served XM307 ACSW. The grenades are shaped like bullets, so they are able to bounce; albeit rarely. Because the grenades the weapon uses are now available in airburst configurations, the weapon can technically fire around corners and tight spaces while still retaining lethality.