During the Vietnam War U.S. Army quickly felt a growing need for an effective sniper rifle. Its creation was entrusted to a special army units - Army marksmanship Unit. The new rifle was developed jointly Army Weapons Command (Rock Island, IL), Combat Development Command (Ft. Benning, Georgia) and Limited Warfare Agency (Aberdeen, MD).
The easiest solution to create a new sniper rifle was refitted in the arsenal of semi-automatic rifles M14 (more precisely, its specially modified for shooting competitions option M14 National Match - M14 NM) under a specially designed optical sight ART (adjustable rangefinder).
For retrofitting into M21 sniper rifle M14 specially selected from the best accuracy of fire.
In a wooden box i>
new sniper rifle was designated the XM21.
In 1969, Rock Island Arsenal (Rock Island Arsenal) has modified more than 1,400 M14 rifles in NM option HM21, and most of them were sent to Vietnam. Part of the rifles was additionally equipped with a silencer shot sound Sionics (silencer does not affect the muzzle velocity, but reduced speed propellant gases to subsonic).
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In 1975 rifle from the experimental (index HM21) officially acquired the status of the armament (M21 index), and was used by the U.S. Army until 1988, when she was adopted to replace the M25 sniper rifle. However, in the army and in the National Guard M21 rifle remained until the war with Iraq in 1991.
M21 used in military operations in Iraq and Afghanistan in the beginning of XXI century.
Sniper Rifle M21 - semi-automatic weapon using the vapor-automatic short-stroke gas piston, located under the barrel. Locking barrel - turning the bolt (Scheme Garand).
Rifle M21 M14 differs from the high precision fabrication of the barrel. Gas chamber and piston manual processing and polished to improve efficiency and reduce carbon deposits: the gas chamber and a lower ring lozhevyh fixedly connected to each other.
| M21 i> |
Trigger manual processing and has a polished surface. The force on the trigger is adjustable from 2.0 to 2.15 kg.
Rifle HM21 had solid wood box with a pistol lip of the cervix. Boxes impregnated with epoxy resin. Later M21 rifles bed was made of fiberglass.
Unlike linear M14 mass production, transmission and receiver were fitted individually M21 bed and fastened with each other a layer of epoxy resin.
| Caliber, mm || 7.62x51 NATO |
| Weight empty, kg || 5.27 |
| Length mm || 1118 |
| Barrel length, mm || 560 |
| Muzzle velocity m / s || 853 |
| Sighting range, m || 800 |
| Capacity count. cartridges || 5, 10, 20 |
M21 rifle retained adjustable sights rifle M14 (diopter rear sight and front sight). Scope mount is installed into the seats formed on the left side of the receiver all production rifles M14. Rifle with an optical sight was completed Leatherwood 3X-9X Adjustable Ranging Telescope (ART) (with rangefinder reticle) or night sight, on a special bracket that provides automatic input amendments firing range for M118 cartridge (option holder 7.62x51 NATO, optimized for precision shooting ).
Reticle Leatherwood 3X-9X ART can fire at ranges up to 1000 m at the maximum effective range of 600-800 m sight has two risks ranging horizontal filament grid corresponding to 152 cm at a distance of 300 m at the three-fold increase and two in the vertical strands 76 cm appropriate under the same conditions. To clarify: the distance from the top of the helmet to the waist belt of a soldier can be taken as 76 cm, ie, at a distance of 300 m when it hits three-fold increase between the two risks in the vertical threads. If the distance is more than 300 m, it is necessary to enlarge the image to fit the gap between the two risks.
clear that the increase in direct proportion to the distance: the same height value at 9-fold increase corresponds to the range of 900 m, and at 3x - 300 m This principle allows the sniper to quickly and accurately determine the distance to the target. Furthermore, the adjusting ring has a ballistic cam that when setting ranging scratches automatically shifts the axis of the sight vertically in accordance with the ammunition used.
rifle can be equipped with adjustable folding bipod.
circular error probable M21 sniper rifle does not exceed an average of 15 cm at a distance of 300 m
Company "Springfield Armory" special orders begun manufacturing modifications M21 with a modified barrel. For better stabilization of the bullet in flight barrel rifling has a somewhat greater slope: stroke length 254 mm rifling. against 305 mm. usual for 7,62 x51. In the bed of the trunk is placed on rubber fiberglass lining.
is also available in M21 with a stock of fiberglass and sight 10X or 3-9x.
In addition, for the U.S. Special Operations forces has been developed under the symbol version of the rifle M25, M21 differed from improved plastic lodge firm McMillan and more modern optical sights firms Baush & Lomb or Leupold on the new brackets.