SR-25
Encyclopedia
The SR-25 is a semi-automatic
sniper 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, rounded) rifling
, with twist 1:11.25 (1 complete turn in 11.25 inches (285.8 mm)). The heavy 20 in (508 mm) barrel is free-floating
, so handguards are attached to the front of the receiver and do not touch the barrel.
-Weaver
rail system, rather than the older Mk 11 free-floating RAS, on the top of the receiver to accept different scope mounts or a carrying handle with iron sights (front sight mounted on the rail located on the forward end of the non-modular handguard). The match version is designed to shoot at a precision of 0.5 minute of arc
, which corresponds to 0.5 inches (12.7 mm) groups at 100 yards (91.4 m).
The Mk 11 Mod 0 system comes in 7.62 mm NATO caliber, and is designed for match-grade 7.62×51mm NATO ammunition. The Mk 11 system includes the rifle, 20 round box magazines, QD (Quick Detachable) scope rings, Leupold Mark 4 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.
The Mk 11 Mod 0 utilizes an Obermeyer 20 in (508 mm) match target barrel, along with a RAS (Rail Accessory System) fore-end made by KAC, consisting of an 11.35 in (288.3 mm) long match fore-end. The RAS allows for quick attachment/detachment of MIL-STD-1913 components. The aluminum fore-end makes no contact with the barrel forward of the receiver, allowing for extreme accuracy. The Mk 11 Mod 0 has an empty weight of 15.3 lb (6.9 kg), and an overall length of 45.4 in (115.3 cm). The civilian version, using the longer 24 in (609.6 mm) match barrel, is guaranteed to produce groupings of less than 1 in (25.4 mm) at 100 yd (91.4 m), or 0.3 angular mil
, using factory match loads.
The new SR-25 Enhanced Match (E.M.) Carbine 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 suppressor. Starting late 2011, USMC snipers will replace Mk11 Mod 0 rifles with the M110 Semi-Automatic Sniper System on a one-for-one basis.
Semi-automatic rifle
A semi-automatic rifle is a type of rifle that fires a single bullet each time the trigger is pulled, automatically ejects the spent cartridge, chambers a fresh cartridge from its magazine, and is immediately ready to fire another shot...
sniper rifle
Sniper rifle
In military and law enforcement terminology, a sniper rifle is a precision-rifle used to ensure more accurate placement of bullets at longer ranges than other small arms. A typical sniper rifle is built for optimal levels of accuracy, fitted with a telescopic sight and chambered for a military...
designed by Eugene Stoner
Eugene Stoner
Eugene Morrison Stoner is the man most associated with the design of the AR-15, which was adopted by the US military as the M16...
and manufactured by Knight's Armament Company
Knight's Armament Company
Knight's Armament Company is an American firearms and firearms parts manufacturer.It is owned by C. Reed Knight and based in Titusville, Florida. KAC is best known for producing the Rail Interface System and the Rail Adapter System grips for military firearms...
. The SR-25 uses a rotating bolt
Rotating bolt
Rotating bolt is a method of locking originally developed by Ferdinand Ritter von Mannlicher and found in his Steyr-Mannlicher M1895 straight-pull bolt-action rifle designed for and issued to the Austro-Hungarian Army...
and a direct impingement
Direct impingement
Direct impingement is a type of gas operation for a firearm that directs gas from a fired cartridge directly to the bolt carrier or slide assembly to cycle the action.- Evaluation :...
gas system. It is loosely based on Stoner's AR-10
AR-10
The AR-10 is an American 7.62 mm battle rifle developed by Eugene Stoner in the late 1950s at ArmaLite, then a division of the Fairchild Aircraft Corporation...
, rebuilt in its original 7.62×51mm NATO
7.62×51mm NATO
The 7.62×51mm NATO is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries...
caliber. Up to 60% of parts of the SR-25 are interchangeable with the AR-15
AR-15
The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....
and M16
M16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...
—everything but the upper and lower receivers
Receiver (firearms)
In firearms terminology, the receiver is the part of a firearm that houses the operating parts. The receiver usually contains the bolt carrier group, trigger group, and magazine port. In most handguns, the receiver, or frame, holds the magazine well or rotary magazine as well as the trigger mechanism...
, the hammer
Hammer (firearm)
thumb|150px|Hammer with an integral [[firing pin]] on a [[S&W Model 13]] revolver The hammer of a firearm was given its name for both resemblance and functional similarity to the common tool...
, the barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
assembly and the bolt
Bolt (firearm)
A bolt is a mechanical part of a firearm that blocks the rear of the chamber while the propellant burns.In manually-operated firearms, such as bolt-action, lever-action, and pump-action rifles and shotguns, the bolt is held fixed by its locking lugs during firing, forcing all the expanding gas...
carrier group. SR-25 barrels were originally manufactured by Remington Arms
Remington Arms
Remington Arms Company, Inc. was founded in 1816 by Eliphalet Remington in Ilion, New York, as E. Remington and Sons. It is the oldest company in the United States which still makes its original product, and is the oldest continuously operating manufacturer in North America. It is the only U.S....
with its 5R (5 grooves, rounded) rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
, with twist 1:11.25 (1 complete turn in 11.25 inches (285.8 mm)). The heavy 20 in (508 mm) barrel is free-floating
Free-floating barrel
A free-floating barrel is a specific design technology used in highly accurate rifles, particularly match grade rifles, to increase the accuracy of the weapon.With normal rifles, the barrel rests in contact with the stock...
, so handguards are attached to the front of the receiver and do not touch the barrel.
Design
The SR-25 enhanced match rifle utilizes the newer URX II PicatinnyPicatinny rail
The Picatinny rail or MIL-STD-1913 rail or STANAG 2324 rail or a "Tactical Rail" is a bracket used on some firearms in order to provide a standardized mounting platform. A similar system is the Weaver rail mount.-Description:...
-Weaver
Weaver rail mount
A Weaver rail mount is a system to connect telescopic sights and other accessories to rifles, shotguns, pistols, archery bows, etc...
rail system, rather than the older Mk 11 free-floating RAS, on the top of the receiver to accept different scope mounts or a carrying handle with iron sights (front sight mounted on the rail located on the forward end of the non-modular handguard). The match version is designed to shoot at a precision of 0.5 minute of arc
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
, which corresponds to 0.5 inches (12.7 mm) groups at 100 yards (91.4 m).
The Mk 11 Mod 0 system comes in 7.62 mm NATO caliber, and is designed for match-grade 7.62×51mm NATO ammunition. The Mk 11 system includes the rifle, 20 round box magazines, QD (Quick Detachable) scope rings, Leupold Mark 4 Mil-dot riflescope, Harris swivel-base bipod on a Knight's mount, and QD sound suppressor
Suppressor
A suppressor, sound suppressor, sound moderator, or silencer, is a device attached to or part of the barrel of a firearm which reduces the amount of noise and flash generated by firing the weapon....
, 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.
The Mk 11 Mod 0 utilizes an Obermeyer 20 in (508 mm) match target barrel, along with a RAS (Rail Accessory System) fore-end made by KAC, consisting of an 11.35 in (288.3 mm) long match fore-end. The RAS allows for quick attachment/detachment of MIL-STD-1913 components. The aluminum fore-end makes no contact with the barrel forward of the receiver, allowing for extreme accuracy. The Mk 11 Mod 0 has an empty weight of 15.3 lb (6.9 kg), and an overall length of 45.4 in (115.3 cm). The civilian version, using the longer 24 in (609.6 mm) match barrel, is guaranteed to produce groupings of less than 1 in (25.4 mm) at 100 yd (91.4 m), or 0.3 angular mil
Angular mil
An angular mil, also mil, is a unit of angle. All versions of the angular mil are approximately the same size as a trigonometric milliradian.-History:The milliradian was first identified in the mid nineteenth Century...
, using factory match loads.
The new SR-25 Enhanced Match (E.M.) Carbine 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 suppressor. Starting late 2011, USMC snipers will replace Mk11 Mod 0 rifles with the M110 Semi-Automatic Sniper System on a one-for-one basis.
Users
- Australian ArmyAustralian ArmyThe Australian Army is Australia's military land force. It is part of the Australian Defence Force along with the Royal Australian Navy and the Royal Australian Air Force. While the Chief of Defence commands the Australian Defence Force , the Army is commanded by the Chief of Army...
and Police Tactical GroupPolice Tactical GroupPolice tactical groups , formerly known as "police assault groups", are part of the Australian government's National Anti-Terrorism Plan which, since 1978, has required each state and territory police force to maintain a specialised counter-terrorist and hostage rescue unit jointly funded by the...
s.: EKAMSpecial Anti-Terrorist UnitThe Special Suppressive Anti-Terrorist Unit is the Greek counter-terrorism unit of the Hellenic Police. It is the most distinguished part of the Hellenic Police...
special forces.: IDFIsrael Defense ForcesThe Israel Defense Forces , commonly known in Israel by the Hebrew acronym Tzahal , are the military forces of the State of Israel. They consist of the ground forces, air force and navy. It is the sole military wing of the Israeli security forces, and has no civilian jurisdiction within Israel...
special forcesSpecial forcesSpecial forces, or special operations forces are terms used to describe elite military tactical teams trained to perform high-risk dangerous missions that conventional units cannot perform...
.: GROMGROMGROM is one of five special forces units of the Polish Armed Forces. It was officially activated on July 8, 1990...
.: Royal Thai Army.: United States Military.
See also
- United States Navy Mark 12 Mod X Special Purpose RifleUnited States Navy Mark 12 Mod X Special Purpose RifleThe United States Navy Mark 12 Mod 0/1 Special Purpose Rifle is a rifle in service with United States Special Operations Forces in Operation Enduring Freedom and Operation Iraqi Freedom...
- List of individual weapons of the U.S. Armed Forces