Tuesday, May 15, 2012

Dragunov sniper rifle


     The Dragunov sniper rifle (formally Russian: Снайперская винтовка Драгунова, Snayperskaya Vintovka Dragunova (SVD), literally "Dragunov's sniper rifle") is a semi-automatic sniper rifle/designated marksman rifle chambered in 7.62×54mmR and developed in the Soviet Union.

     The Dragunov was designed as a squad support weapon, since according to Soviet and Soviet-derived military doctrines the long-range engagement ability was lost to ordinary troops when submachine guns and assault rifles (which are optimized for close-range and medium-range, rapid-fire combat) were adopted. For that reason it was originally named "Полуавтоматическая винтовка Драгунова" Dragunov's Semi-automatic Rifle.

     It was selected as the winner of a contest that included three competing designs: the first was a rifle designed by Sergei Simonov (known as the SSV-58), the second design, a prototype designated 2B-W10 by Alexander Konstantinov, and the third rifle, the SVD-137, a design submitted by Yevgeny Dragunov. Extensive field testing of the rifles conducted in a wide range of environmental conditions resulted in Dragunov’s proposal being accepted into service in 1963. An initial pre-production batch consisting of 200 rifles was assembled for evaluation purposes, and from 1964 serial production was carried out by Izhmash.

     Since then, the Dragunov has become the standard squad support weapon of several countries, including those of the former Warsaw Pact. Licensed production of the rifle was established in China (Type 79 and Type 85) and Iran (as a direct copy of the Chinese Type 79).


Operating mechanism

     The Dragunov is a semi-automatic gas-operated rifle with a short-stroke gas-piston system. The barrel breech is locked through a rotating bolt (left rotation) and uses three locking lugs to engage corresponding locking recesses in the barrel extension. The rifle has a manual, two-position gas regulator.

     After discharging the last cartridge from the magazine, the bolt carrier and bolt are held back on a bolt catch that is released by pulling the cocking handle to the rear. The rifle has a hammer-type striking mechanism and a manual lever safety selector. The rifle's receiver is machined to provide additional accuracy and torsional strength. The Dragunov's receiver bears a number of similarities to the AK action, such as the large dust cover, iron sights and lever safety selector, but these similarities are primarily cosmetic in nature.


Features

    The weapon is fed from a curved box magazine with a 10-round capacity and the cartridges are double-stacked in a checker pattern.

     The Dragunov's barrel is ended with a slotted flash suppressor. The barrel’s bore is chrome-lined[3] for increased corrosion resistance, and has 4 right-hand grooves with a 320 mm (1:12.6 in) twist rate. The rifled part of the barrel is 547 mm (21.5 in). Later the twist rate was tightened to 240 mm (1:9.4 in) which slightly reduces the accuracy of fire with sniper cartridges and reduces the muzzle velocity to 810 m/s (2,657.5 ft/s). This was done in order to facilitate the use of tracer and armor-piercing incendiary ammunition. These special bullet types required a shorter twist rate for adequate stabilization.[4]

     For precision shooting, specifically designed sniper cartridges are used, developed by V. M. Sabelnikov, P. P. Sazonov and V. M. Dvorianinov. The proprietary 7N1 load has a steel jacketed projectile with an air pocket, a steel core and a lead knocker in the base for maximum terminal effect. The 7N1 was replaced in 1999 by the 7N14 round. The 7N14 is a new load developed for the SVD. It consists of a 151 grain projectile which travels at the same 830 m/s, but it has a sharp hardened steel core projectile. The rifle can also fire standard 7.62×54mmR ammunition with either conventional, tracer or armor piercing incendiary rounds.

     The Russian military has established accuracy standards the SVD and its corresponding sniper grade ammunition have to meet. Manufacturers must perform firing tests to check if the rifles and sniper grade ammunition fulfill these standards. To comply to the standards the SVD rifle with 7N1 sniper cartridges may not produce more than 1.24 MOA extreme vertical spread with 240 mm twist rate barrels and no more than 1.04 MOA extreme vertical spread with 320 mm twist rate barrels. When using standard grade 57-N-323S cartridges the accuracy of the SVD is reduced to 2.21 MOA extreme vertical spread. The extreme vertical spreads for the SVD are established by shooting 5-shot groups at 300 m range. The accuracy requirements demanded of the SVD with sniper grade ammunition are similar to the American M24 Sniper Weapon System with M118SB cartridges (1.18 MOA extreme vertical spread) and the M110 Semi-Automatic Sniper System with M118LR ammunition (1.27 MOA extreme vertical spread).

     The Dragunov has a vented, two-piece wooden handguard/gas tube cover and a skeletonized wooden thumbhole stock equipped with a detachable cheek rest; the latter is removed when using iron sights. Newer production models feature synthetic furniture made of a black polymer - the handguard and gas tube cover are more or less identical in appearance, while the thumbhole stock is of a different shape.

Sights

     The rifle features mechanically adjustable backup iron sights with a sliding tangent rear sight (the sight can
be adjusted to a maximum range of 1,200 m). The iron sights can be used with or without the standard issue optical sight in place. This is possible because the scope mount does not block the area between the front and rear sights.

     The Dragunov is issued with a quick-detachable PSO-1 optical sight. The PSO-1 sight (at a total length of 375 mm with a lens cover and sun shade, 4x magnification and 6° field of view) mounts to a proprietary side rail mount that does not block the view of the iron sight line. The PSO-1 sight includes a variety of features, such as a bullet drop compensation (BDC) elevation adjustment knob, an illuminated rangefinder grid, a
reticle that enables target acquisition in low light conditions as well as an infrared charging screen that is used as a passive detection system. The PSO-1 sight enables targets to be engaged at ranges upwards of 1,300 m; effective ranges in combat situations have been stated at between 600 to 1,300 m, depending on the nature of the target (point or area target) quality of ammunition and skill of the shooter.
Several other models of the PSO sight are available with varying levels of magnification and alternative aiming reticulesRifles designated SVDN come equipped with a night sight, such as the NSP-3, NSPU, PGN-1, NSPUM or the Polish passive PCS-6 and can be used to engage targets at night.

Accessories

     A number of accessories are provided with the rifle, including a blade-type bayonet (AKM clipped point or the AK-74 spear point bayonet), four spare magazines, a leather or nylon sling, magazine pouch, cleaning kit and an accessory/maintenance kit for the telescopic sight.


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