The Sniper Rifle 2/3
Distinguishing Characteristics
The features of a sniper rifle can vary widely depending on the specific tasks it is intended to perform. Features that may distinguish a sniper rifle from other weapons are the presence of a telescopic sight, unusually long overall length, a stock designed for firing from a prone position, and the presence of a bipod and other accessories.
Telescopic Sights
A designated marksman rifle (DMR) is less specialized than a typical military sniper rifle, often only intended to extend the range of a group of soldiers. Therefore, when a semi-automatic action is used it is due to its ability to cross over into roles similar to the roles of standard issue weapons. There may also be additional logistical advantages if the DMR uses the same ammunition as the more common standard issue weapons. These rifles enable a higher volume of fire, but sacrifice some long range accuracy. They are frequently built from existing selective fire battle rifles or assault rifles, often simply by adding a telescopic sight and adjustable stock.
A police semi-automatic sniper rifle may be used in situations that require a single sniper to engage multiple targets in quick succession, and military semi-automatics such as the M110 SASS are used in similar "target-rich" environments
Cartridge
In a military setting, logistical concerns are the primary determinant of the cartridge used, so sniper rifles are usually limited to rifle cartridges commonly used by the military force employing the rifle. Since large national militaries generally change slowly, military rifle ammunition is frequently battle-tested and well-studied by ammunition and firearms experts. Consequently, police forces tend to follow military practices in choosing a sniper rifle cartridge instead of trying to break new ground with less-perfected (but possibly better) ammunition.
Before the introduction of the standard 7.62x51mm_NATO cartridge in the 1950s, standard military cartridges were the .30-06 Springfield or 7.62x63mm (United States), .303 British (7.7x56mmR) (United Kingdom) and 7.92x57mm (8mm Mauser) (Germany). The .30-06 Springfield continued in service with U.S. Marine Corps snipers during the Vietnam War in the 1970s, well after general adoption of the 7.62x51mm. At the present time, in both the Western world and within NATO, 7.62x51mm is currently the primary cartridge of choice for military and police sniper rifles.
Worldwide, the trend is similar. The preferred sniper cartridge in Russia is another .30 calibre military cartridge, the 7.62 x 54 mm R, which has similar performance to the 7.62x51mm. This cartridge was introduced in 1891, and both Russian sniper rifles of the modern era, the Mosin-Nagant and the Dragunov sniper rifle, are chambered for it.
Certain commercial cartridges designed with only performance in mind, without the logistical constraints of most armies, have also gained popularity in the 1990s. These include the 7 mm Remington Magnum (7.2x64mm), .300 Winchester Magnum (7.8/7.62x67mm), and the .338 Lapua Magnum (8.6x70mm). These cartridges offer better ballistic performance and greater effective range than the 7.62x51mm. Though they are not as powerful as .50 calibre cartridges they are not as heavy as rifles chambered for .50 calibre ammunition, and are significantly more powerful than rifles chambered for 7.62x51mm.
M82A1 SASR (Special Applications Scoped Rifle), a .50 calibre sniper rifle used as an anti-materiel rifle.
Snipers may also employ anti-materiel rifles in sniping roles against targets such as vehicles, equipment and structures, or for the long-range destruction of explosive devices; these rifles may also be used against personnel.
Anti-materiel rifles tend to be semi-automatic and of a larger calibre than anti-personnel rifles, using cartridges such as the .50 BMG, 12.7x108mm Russian or even 14.5x114mm Russian and 20mm. These large cartridges are required to be able to fire projectiles containing payloads such as explosives, armour piercing cores, incendiaries or combinations of these, such as the Raufoss Mk211 projectile. Due to the considerable size and weight of anti-materiel rifles, 2- or 3-man sniper teams become necessary.
Barrel
Barrels are normally of precise manufacture and of a heavier cross section than more traditional barrels in order to reduce the change in impact points between a first shot from a cold barrel and a follow-up shot from a warm barrel. Unlike many battle and assault rifles, the bores are usually not chromed to avoid inaccuracy due to an uneven treatment.
When installed, barrels are often free-floated, i.e., installed so the barrel only contacts the rest of the rifle at the receiver, to minimise the effects on impact point of pressure on the fore-end by slings, bipods, or the sniper's hands. The end of the barrel is usually crowned or machined to form a rebated area around the muzzle proper to avoid asymmetry or damage, and consequent inaccuracy. Alternatively, some rifles such as the Dragunov or Walther WA2000 provide structures at the fore-end to provide tension on the barrel in order to counteract barrel drop and other alterations in barrel shape.
External longitudinal fluting that contributes to heat dissipation by increasing surface area while simultaneously decreasing the weight of the barrel is sometimes used on sniper rifle barrels.
Sniper rifle barrels may also utilise a threaded muzzle or combination device (muzzle brake or flash suppressor and attachment mount) to allow the fitting of a sound suppressor. These suppressors often have means of adjusting the point of impact while fitted.
Military sniper rifles tend to have barrel lengths of 600 mm (24 inches) or longer, to allow the cartridge propellant to fully burn, reducing revealing muzzle flash and increasing bullet velocity. Police sniper rifles may use shorter barrels to improve handling characteristics. The shorter barrels' velocity loss is unimportant at closer ranges; projectile energy is more than sufficient.
[edit] Stock
The most common special feature of a sniper rifle stock is the adjustable cheek piece, where the shooter's cheek meets the rear of the stock. For most rifles equipped with a telescopic sight, this area is raised slightly, because the telescope is positioned higher than iron sights. A cheek piece is simply a section of the stock that can be adjusted up or down to suit the individual shooter. To further aid this individual fitting, the stock can sometimes also be adjusted for length, often by varying the number of inserts at the rear of the stock where it meets the shooter's shoulder. Sniper stocks are typically designed to avoid making contact with the barrel of the weapon.
Accessories
An adjustable sling is often fitted on the rifle, used by the sniper to achieve better stability when standing, kneeling, or sitting. The sniper uses the sling to "lock-in" by wrapping their non-firing arm into the sling forcing their arm to be still. Non-static weapon mounts such as bipods, monopods and shooting sticks are also regularly used to aid and improve stability and reduce operator fatigue.
From Wikipedia
The Free Encyclopedia
The features of a sniper rifle can vary widely depending on the specific tasks it is intended to perform. Features that may distinguish a sniper rifle from other weapons are the presence of a telescopic sight, unusually long overall length, a stock designed for firing from a prone position, and the presence of a bipod and other accessories.
Telescopic Sights
The single most important characteristic that sets a sniper rifle apart from other military or police small arms is the mounting of a telescopic sight, which is relatively easy to distinguish from smaller optical aiming devices found on some modern assault rifles and submachine guns. This also allows the user to see farther.
The telescopic sights used on sniper rifles differ from other optical sights in that they offer much greater magnification (more than 4x and up to 40x), and have a much larger objective lens (40 to 50 mm in diameter) for a brighter image.
Most telescopic lenses employed in military or police roles have special reticles to aid with judgment of distance, which is an important factor in accurate shot placement due to the bullet's trajectory.
Action
The choice between bolt-action and semi-automatic (more commonly recoil or gas operation) is usually determined by specific requirements of the sniper's role as envisioned in a particular organization, with each design having advantages and disadvantages. For a given cartridge, a bolt-action rifle is cheaper to build and maintain, more reliable, and lighter, due to fewer moving parts in the mechanism. In addition, the lack of an external magazine allows for more versatile fire-positioning, and the absence of uncontrolled automatic cartridge case ejection helped to avoid revealing the firer's position. Semi-automatic weapons can serve both as battle rifle and sniper rifle, and allow for a greater rate (and hence volume) of fire. As such rifles may be modified service rifles, an additional benefit can be commonality of operation with the issued infantry rifle. A bolt action is most commonly used in both military and police roles due to its higher accuracy and ease of maintenance. Anti-materiel applications such as mine clearing and special forces operations tend to use semi-automatics.A designated marksman rifle (DMR) is less specialized than a typical military sniper rifle, often only intended to extend the range of a group of soldiers. Therefore, when a semi-automatic action is used it is due to its ability to cross over into roles similar to the roles of standard issue weapons. There may also be additional logistical advantages if the DMR uses the same ammunition as the more common standard issue weapons. These rifles enable a higher volume of fire, but sacrifice some long range accuracy. They are frequently built from existing selective fire battle rifles or assault rifles, often simply by adding a telescopic sight and adjustable stock.
A police semi-automatic sniper rifle may be used in situations that require a single sniper to engage multiple targets in quick succession, and military semi-automatics such as the M110 SASS are used in similar "target-rich" environments
Cartridge
In a military setting, logistical concerns are the primary determinant of the cartridge used, so sniper rifles are usually limited to rifle cartridges commonly used by the military force employing the rifle. Since large national militaries generally change slowly, military rifle ammunition is frequently battle-tested and well-studied by ammunition and firearms experts. Consequently, police forces tend to follow military practices in choosing a sniper rifle cartridge instead of trying to break new ground with less-perfected (but possibly better) ammunition.
Before the introduction of the standard 7.62x51mm_NATO cartridge in the 1950s, standard military cartridges were the .30-06 Springfield or 7.62x63mm (United States), .303 British (7.7x56mmR) (United Kingdom) and 7.92x57mm (8mm Mauser) (Germany). The .30-06 Springfield continued in service with U.S. Marine Corps snipers during the Vietnam War in the 1970s, well after general adoption of the 7.62x51mm. At the present time, in both the Western world and within NATO, 7.62x51mm is currently the primary cartridge of choice for military and police sniper rifles.
Worldwide, the trend is similar. The preferred sniper cartridge in Russia is another .30 calibre military cartridge, the 7.62 x 54 mm R, which has similar performance to the 7.62x51mm. This cartridge was introduced in 1891, and both Russian sniper rifles of the modern era, the Mosin-Nagant and the Dragunov sniper rifle, are chambered for it.
Certain commercial cartridges designed with only performance in mind, without the logistical constraints of most armies, have also gained popularity in the 1990s. These include the 7 mm Remington Magnum (7.2x64mm), .300 Winchester Magnum (7.8/7.62x67mm), and the .338 Lapua Magnum (8.6x70mm). These cartridges offer better ballistic performance and greater effective range than the 7.62x51mm. Though they are not as powerful as .50 calibre cartridges they are not as heavy as rifles chambered for .50 calibre ammunition, and are significantly more powerful than rifles chambered for 7.62x51mm.
M82A1 SASR (Special Applications Scoped Rifle), a .50 calibre sniper rifle used as an anti-materiel rifle.
Snipers may also employ anti-materiel rifles in sniping roles against targets such as vehicles, equipment and structures, or for the long-range destruction of explosive devices; these rifles may also be used against personnel.
Anti-materiel rifles tend to be semi-automatic and of a larger calibre than anti-personnel rifles, using cartridges such as the .50 BMG, 12.7x108mm Russian or even 14.5x114mm Russian and 20mm. These large cartridges are required to be able to fire projectiles containing payloads such as explosives, armour piercing cores, incendiaries or combinations of these, such as the Raufoss Mk211 projectile. Due to the considerable size and weight of anti-materiel rifles, 2- or 3-man sniper teams become necessary.
Barrel
Barrels are normally of precise manufacture and of a heavier cross section than more traditional barrels in order to reduce the change in impact points between a first shot from a cold barrel and a follow-up shot from a warm barrel. Unlike many battle and assault rifles, the bores are usually not chromed to avoid inaccuracy due to an uneven treatment.
When installed, barrels are often free-floated, i.e., installed so the barrel only contacts the rest of the rifle at the receiver, to minimise the effects on impact point of pressure on the fore-end by slings, bipods, or the sniper's hands. The end of the barrel is usually crowned or machined to form a rebated area around the muzzle proper to avoid asymmetry or damage, and consequent inaccuracy. Alternatively, some rifles such as the Dragunov or Walther WA2000 provide structures at the fore-end to provide tension on the barrel in order to counteract barrel drop and other alterations in barrel shape.
External longitudinal fluting that contributes to heat dissipation by increasing surface area while simultaneously decreasing the weight of the barrel is sometimes used on sniper rifle barrels.
Sniper rifle barrels may also utilise a threaded muzzle or combination device (muzzle brake or flash suppressor and attachment mount) to allow the fitting of a sound suppressor. These suppressors often have means of adjusting the point of impact while fitted.
Military sniper rifles tend to have barrel lengths of 600 mm (24 inches) or longer, to allow the cartridge propellant to fully burn, reducing revealing muzzle flash and increasing bullet velocity. Police sniper rifles may use shorter barrels to improve handling characteristics. The shorter barrels' velocity loss is unimportant at closer ranges; projectile energy is more than sufficient.
[edit] Stock
The most common special feature of a sniper rifle stock is the adjustable cheek piece, where the shooter's cheek meets the rear of the stock. For most rifles equipped with a telescopic sight, this area is raised slightly, because the telescope is positioned higher than iron sights. A cheek piece is simply a section of the stock that can be adjusted up or down to suit the individual shooter. To further aid this individual fitting, the stock can sometimes also be adjusted for length, often by varying the number of inserts at the rear of the stock where it meets the shooter's shoulder. Sniper stocks are typically designed to avoid making contact with the barrel of the weapon.
Accessories
An adjustable sling is often fitted on the rifle, used by the sniper to achieve better stability when standing, kneeling, or sitting. The sniper uses the sling to "lock-in" by wrapping their non-firing arm into the sling forcing their arm to be still. Non-static weapon mounts such as bipods, monopods and shooting sticks are also regularly used to aid and improve stability and reduce operator fatigue.
From Wikipedia
The Free Encyclopedia
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