Mark 11 Mod 0 Sniper Weapon System

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, Operation Enduring Freedom - Philippines, Zamboanga City crisis, Battle of Marawi, 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. The heavy 24-inch (610 mm) barrel is free-floating, so handguards are attached to the front of the receiver and do not touch the barrel.

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.

In the early 1990s, Stoner joined Knight's Armament Company. He continued his AR-10 design work and joined it with the direct gas system of the AR-15. The end result was the SR-25 (adding together the numbers of the AR-10 and AR-15) which improved the AR-10 design with M16A2 advancements and parts commonality. The original SR-25 was released in the early 1990s and had a heavy free-floating 24 in (610 mm) match grade barrel with a fiberglass handguard. It had a flat top upper receiver with a Mil-Std 1913 rail for mounting optics and a 2-stage match grade trigger. The bolt carrier was similar to the AR-10's, being chrome plated and having a captive firing pin retainer pin. The SR-25 was designed specifically to fire 168 gr (10.9 g) open-tip match cartridges. Accuracy was guaranteed at or under 1 minute of angle. At first, AR-10 type 20-round magazines were used, but they were later replaced by steel 20-round magazines resembling those used by the M16.