Stoner Rifle 25

SR-25
A SR-25 outfitted with a riflescope, bipod and a detachable suppressor
Type	Designated marksman rifle
Place of origin	United States
Service history
In service	1990–present
Used by	See Users
Wars	Afghanistan War, Iraq War, 2006 East Timorese crisis, 2nd Intifada
Production history
Designer	Eugene Stoner
Manufacturer	Knight's Armament Company
Variants	SR-25 Enhanced Match rifle, with 20 in (510 mm) barrel SR-25 Enhanced Match Carbine, with 16 in (410 mm) barrel and M110 flash suppressor
Specifications
Weight	Match Rifle 10.75 lb (4.88 kg), LwMatch 9.5 lb (4.3 kg), Carbine 7.5 lb (3.4 kg), Sporter 8.75 lb (3.97 kg)
Length	1,118 mm (44.0 in)
Barrel length	Match Rifle 24 in (610 mm) (also LwMatch & Sporter 20 in or 510 mm, Carbine 16 in or 410 mm)
Cartridge	7.62×51mm NATO
Action	Gas-operated, rotating bolt
Rate of fire	Semi-automatic
Feed system	10 and 20-round detachable box magazine

SR-25 Enhanced Match rifle, with 20 in (510 mm) barrel

Match Rifle 24 in (610 mm)

The SR-25 (Stoner Rifle-25) is a designated marksman rifle designed by Eugene Stoner and manufactured 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, rebuilt in its original 7.62×51mm NATO caliber. Up to 60% of parts of the SR-25 are interchangeable with the AR-15 and M16—everything but the upper and lower receivers, the hammer, the barrel assembly and the bolt carrier group. SR-25 barrels were originally manufactured by Remington Arms with its 5R (5 grooves, right twist) rifling, with twist 1:11.25 (1 complete turn in 11.25 inches or 286 millimetres). The heavy 24 in (610 mm) barrel is free-floating, so handguards are attached to the front of the receiver and do not touch the barrel.

First military purchase was spearheaded by the U.S. Navy in the early 1990s; the first operational deployment and use of the SR-25 sniper rifle was with U.S. Navy SEAL snipers supporting operations in Somalia in 1993.

In the late 1950s, Eugene Stoner designed the AR-10 battle rifle to equip U.S. troops. It was accurate for an auto-loading rifle, but it lost the competition to the M14 rifle. The patent rights for the AR-10 and the AR-15 were sold to Colt's Manufacturing Company. Colt focused on the AR-15, giving others the ability to capitalize on the AR-10 system.