SR-25


 * For State Route 25 or State Road 25, see list of highways numbered 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.

[[united states|🇺🇸]] US Navy
The United States Navy Mk 11 Mod 0 Sniper Weapon System (NATO Stock Number 1005-01-475-7980) is a complete rifle system based around the highly accurate Knight's Armament Company SR-25 semi-automatic rifle. It was originally conceived and constructed to meet a requirement placed by the U.S. Navy SEALs.

The Mk 11 Mod 0 has received worldwide recognition as one of the most accurate and durable semi-automatic rifle systems in existence. It is currently in service with most operational components of United States Special Operations Command and also with the Israeli Special Forces. The system has also recently become available to civilian consumers at a unit price of around $7,500 USD; however, it lacks the sound suppressor unit.

The Mk 11 Mod 0 system uses match grade 7.62x51mm NATO ammunition. The Mk 11 system includes the rifle, 20 round box magazines, QD scope rings, Leupold Vari-X Mil-dot riflescope, Harris swivel-base bipod on a Knight's mount, and QD sound suppressor, which is also manufactured by Knight's Armament Co. Flip-up BUIS (Back up iron sights) are attached to the modified gas block and upper receiver.

According to Knight's Armament Company, the heart of the Mk 11 system is the free-floated RAS (Rail Accessory System) fore-end. The aluminum fore-end makes no contact with the barrel forward of the receiver, allowing for extreme accuracy. The Mk 11 Mod 0 uses the KAC 11.35 in (288 mm) long match RAS fore-end, which allows for quick attachment/detachment of MIL-STD-1913 components.

The civilian versions are guaranteed to produce groupings using factory match loads of less than 1 inch at 100 yards (25 mm at 100 m) or 0.3 angular mil.

The Mk 11 Mod 0 System is very similar to the KAC M110 Semi-Automatic Sniper System, though the M110 utilizes the newer URX Rail system, a length-adjustable fixed buttstock, and an integrated flash hider.

The Mk 11 Mod 0 is not capable of fully automatic fire; it is a semi-automatic rifle.

Note that the KAC SR-25, which is the basis of the Mk 11 Mod 0 system, is different from the M21 Sniper Rifle used for a time by USSOCOM. Although they both fire match grade 7.62x51mm NATO ammunition, the M21 is a modified, accurized M14, while the KAC SR-25 is essentially a derivative of the AR-10, the predecessor to the AR-15 and M16 family of assault rifles.

[[united states|🇺🇸]] US Marine Corps
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 the urban environment. 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."

[[united states|🇺🇸]] US Army
In late 2005, the US Army awarded a contract to Knight’s Armament for the M110 Semi-Automatic Sniper System, a variant of the Mk 11, to replace the service’s M24 bolt-action sniper rifles. The Army plans to field 4,400 of the rifles through 2009.

[[israel|🇮🇱]] Israeli Defence Forces
During the late 90's, Israeli Special Forces individually acquired some SR-25 rifles in order to fulfill the need for accurate but rapid mid-range fire. In 2001 it was officially adopted by all Israeli Defence Forces infantry-oriented units. The SR-25 is expected to bridge the gap between the long-range bolt-action M24 Sniper Weapon System, and the shorter-range M16A2E3 designated marksman rifle and M4A1 carbine.

[[australia|🇦🇺]] Australian Army
The SR-25 has recently been observed in service with various units of the Australian Army. It has been fielded in operations in Iraq, Afghanistan and East Timor.

Blackwater Baghdad shootings
In their report after the incident on September 16, 2007, one Blackwater USA guard wrote "I fired one shot from my SR-25 at the closest threat," wrote the guard, referring to a semi-automatic sniper rifle. "He went down and did not fire anymore."

Comparison of the SR25, AR10, and Variants
The SR-25, the current production ArmaLite AR-10, and the DPMS LR308(A3) are all similarly based .308 semi-automatic weapons systems. However, there are differences. The SR-25 does not use a forward assist like the LR308, but the SR-25, LR308, and original production AR-10 can use the same magazines. (The current AR-10 uses a modified M14 magazine). The SR-25 does not use a spring secured firing pin (to prevent accidental firing upon dropping of the weapon) as used in the AR-10. Moreover, the SR-25 uses its own design of recoil spring and synthetic buffer, which is not shared by either the LR308 or the AR10.