M21 Sniper Weapon System
|Rifle, 7.62 mm, Sniper, M21|
M21 sniper rifle
|Place of origin||United States|
|Used by||United States Army, Philippine Army|
|Designer||Marines Weapons Command,
Combat Development Command,
Limited Warfare Agency
|Manufacturer||Rock Island Arsenal, Springfield Armory|
|Weight||5.27 kg (11.6 lb)|
|Length||1118 mm (44 in)|
|Barrel length||560 mm (22 in)|
|Action||Gas-operated, rotating bolt|
|Muzzle velocity||853 m/s (2,800 ft/s)|
|Effective range||822 m (900 yd)|
|Feed system||5, 10 or 20-round detachable box magazine|
|Sights||Front: National Match front blade .062
Rear: Match-grade hooded aperture with one-half minute adjustments for both windage and elevation.
26¾ in sight radius.
The United States Army wanted an accurate sniper rifle during the Vietnam War. The M14 was selected because of its accuracy, reliability, and the ability for a quick second shot. As a result, in 1969, the Rock Island Arsenal converted 1,435 National Match (target grade) M14s by adding a Leatherwood 3–9× Adjustable Ranging Telescope and providing National Match grade ammunition. It was designated the M21 in 1975. The M21 remained the Army's primary sniper rifle until 1988, when it was replaced by the M24 Sniper Weapon System; some M21s were later re-issued and used in the Iraq War.
In standard military use, the M21 uses a 20 round box magazine as the other members of the M14 family and weighs 11 pounds (5.27 kg) without the scope. The U.S. military never officially authorized or purchased magazines in any other capacity, although 5- and 10-round magazines are available.
M25 Sniper Weapon System 
The M25 is an upgraded version of the M21 developed by 10th Special Forces Group's armorers for use by United States Army Special Forces and United States Navy SEALs in the late 1980s. It saw some use during Operation Desert Storm in January and February 1991.
Technical specifications 
- Action: A M14NM (National Match) action.
- Stock: A McMillan M1A fiberglass stock
- Optics: A Bausch & Lomb Tactical 10×40 scope, or sometimes Leupold MK4 10× scopes.
- Bipod: A Harris bipod is often attached for stability during prone firing.
The XM21 Sniper Weapon System was used by the U.S. Army in the Vietnam War, and saw limited action in military conflicts and operations in the late 1960s until the late 1980s. There are limited numbers in some Army National Guard units and in a few specialized active units such as the OPFOR units of the Joint Readiness Training Center.
Springfield Armory, Inc. also manufactures variants of its M1A rifle called M21 Tactical Rifle and M25 White Feather Tactical/Carlos Hathcock rifle, which are based upon M21 and M25 Sniper Weapon Systems but are slightly different, most notably they are fitted with a Picatinny rail to mount a scope.
See also 
- "U.S. Army M21 & XM21 Sniper Weapon System". Sniper Central.
- Springfield Armory, Inc.'s official pages of the M21 Tactical Rifle and M25 White Feather Tactical/Carlos Hathcock model
|Wikimedia Commons has media related to: M21|
- M21 Tactical
- U.S. Army Field Manual 23–10, Appendix B: M21 Sniper Weapon System
- Lee Emerson's Word doc. on the M14 and nearly all known variants
- SniperCentral's page about the M21
- Brief M21 description and history from the U.S. Army.
- M21 on Global Security.org (the same text can be found at FAS.org)
- M25 at SniperParadise.com
- M25 at AnySoldier.com