Weapon 1 : Sniper Rifle, SR-25

The SR-25 (Stoner Rifle-25) is a semi-automatic sniper rifle designed by Eugene Stoner and made by Knight's Armament Company. The SR-25 uses a rotating bolt and a direct impingement gas system. It is loosely based on Stoner's AR-10 (and therefore on the AR-15/M16), rebuilt in its original 7.62x51mm NATO caliber. Up to 60% of parts of the SR-25 are interchangeable with the AR15/M16 - everything but the receiver, the hammer, the barrel assembly and the carrier/bolt. SR-25 barrels were originally manufactured by Remington Arms with its famous 5R (5 grooves, rounded) rifling, with twist 1:11.25 (1 turn in 11.25" (286 mm)). The heavy 24" (609 mm) barrel is free-floating, so handguards are attached to the front of the receiver and do not touch the barrel.

Weapon System Composition
The SR-25 match rifle has no iron sights, and all models have a Picatinny-Weaver rail system on the top of the receiver to accept different scope mounts or M16A4 carrying handle with iron sights (front sight mounted on the rail located on the forward end of the non-modular handguard). It is designed to shoot at a precision of 1 Minute of angle, which corresponds to 1-inch groups at 100 yards, or 6-inch groups at 600 yards, etc.

The SR25M is in use with the US Marine Corps as a sniper rifle. In November, 2005, the USMC announced it was buying 180 Mk 11 Mod 0 rifles in response to an emergency request from II Marine Expeditionary Force commanders in Iraq. The bolt-action M40 sniper rifle currently in use is reportedly not ideally suited for urban environments. According to the Army Times, "the 20-round magazine and higher rate of fire also helps make the Mk 11 a defensive weapon, eliminating the need for snipers to carry three weapons — the M40A3, an M16A4 rifle and M9 pistol — on their way to a hide, snipers say." An added advantage of the Mk 11, according to Army Times, "particularly in an urban fight where the enemy lurks among the population sharing the roads and alleys with Marines on patrol, is the rifle’s resemblance to a standard M16A4."