Sniper rifle

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Sniper rifle is a term applied to a wide range of rifles specifically designed or adapted for military or law enforcement use that ensures accurate placement of shots at ranges normally exceeding those of other small arms. A typical sniper rifle will be engineered for the highest possible levels of accuracy, fitted with a telescopic sight, and chambered for a military centrefire cartridge. The term is often used in the media to describe any type of accurized firearm fitted with a telescopic sight that is employed against human targets.

The M40, United States Marine Corps' standard-issue sniper rifle

History

File:Sniper Rifle Mosin 1891 30.jpg
During World War II, the Mosin-Nagant rifle mounted with a telescopic sight (scope) was commonly used as a sniper rifle by Russian snipers.

The military role of sniper dates back to the turn of the 18th century but the sniper rifle is a much more recent development. Advances in technology, specifically that of telescopic sights and more accurate manufacturing, allowed armies to equip specially-trained soldiers with rifles that would enable them to deliver precise shots over greater distances than regular infantry weapons. The rifle itself could be a standard rifle (at first, a bolt-action rifle); however, when fitted with a telescopic sight, it would become a sniper rifle.

World War I

The earliest sniper rifles were little more than conventional military or target rifles with long-range "peep sights" designed for use on the target range. Only from the beginning of the First World War did specially-adapted sniper rifles come to the fore, with one of the first scoped military sniper rifles being the SMLE Mk III* (HT).

World War II

Typical World War II-era sniper rifles were generally standard-issue rifles (hand-picked for accuracy) with a 2.5x telescopic sight and cheek-rest fitted, with the bolt turned down (if necessary) to allow operation with the scope affixed. By the end of the war, forces on all sides had specially-trained soldiers equipped with sniper rifles, and they have played an increasingly important role in military operations ever since.

Examples of sniper rifles used during World War II:

Classification

Modern sniper rifles can be generally divided into two basic classes: military and law enforcement.

Military

File:040521-M-1012W-013usmc.jpg
U.S. Marine Corps sniper team with a bolt-action M40 sniper rifle, during sniper training

Sniper rifles aimed at military service often sacrifice a small degree accuracy for durability, reliability and ease of operation under battlefield conditions. Military snipers and sharpshooters might also be required to carry their rifles—along with other equipment—for long distances, and as such weight considerations are very important. Military organizations often operate under strict budgetary constraints, which could influence the type and quality of sniper rifles just as it would any other weapon system.

The following are examples of semi-automatic anti-personnel military sniper rifles. The cartridge used in each weapon is in parenthesis:

The following are examples of bolt-action military sniper rifles. The cartridge used in each weapon is in parenthesis:

Law enforcement

File:HK-Psg1.jpg
Heckler & Koch PSG1

Police/law enforcement (and, more recently, counter-terrorism) scenarios require the sniper or sharpshooter to hit a particular part of the agressor's body (such as the head or hand), or a specific object (such as a weapon). For this reason, sniper rifles used by police forces are generally required to have greater accuracy over military rifles, but at shorter ranges—often less than 100 meters.

Some of the first examples of sniper rifles designed specifically to meet police requirements were those designed to meet West German police requirements following the Munich massacre at the 1972 Summer Olympics. The Heckler & Koch PSG1 is one of the rifles designed to meet these criteria, and is often referred to as an ideal example of this type of sniper rifle. The FN Special Police Rifle is another example of a rifle aimed at law enforcement rather than military agencies.

Some of the main differences of police sniper rifles when compared to military rifles are:

  • Shorter overall length for increased maneuverability in urban areas
  • Heavier weight
  • Superior accuracy and tighter tolerances in construction
  • Extreme outdoors durability is of less concern
  • Higher price since budgetary restrictions on police departments often allow more expensive rifles to be acquired

Distinguishing characteristics

Sniper rifle features 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 weapon length[1]
  • Stock designed for firing from a prone position, often incorporating a pistol grip or thumbhole stock (on bolt-action rifles)
  • Fitted with a bipod
  • The range of accessories carried with the rifle
  • Improved accuracy
  • Not specifically designed for sporting use

Telescopic sight

 
Looking through a telescopic sight

The single most important characteristic that sets a sniper rifle apart of other military or police small arms is the mounting of a telescopic sight, which is relatively easily distinguishable from smaller optical aiming devices found on some modern assault rifles and submachine guns.

A telescopic sight allows a person to see farther by virtue of the magnified image it offers, and therefore aim the rifle more accurately. The telescopic sights used on sniper rifles differ from other optical aiming devices in that they offer much greater magnification (more than 4x and up to 10–20x) and much larger objective lens (40 mm in diameter). Most telescopic lenses employed in military or police roles have special markings to aid the shot with the judgement of distance, which is an important factor in accurate shot placement (due to the curved trajectory of a bullet's path).

Action

File:RackandchamberM40A3.jpg
A Marine manually extracts and chambers a new round in his bolt-action M40A3 sniper rifle. The bolt handle is held in the shooter's hand and is not visible in this photo
File:FRF2 1.jpg
French Mountain Infantry firing his bolt-action FRF2. Note the manually-operated bolt handle near the sniper's trigger-finger
 
A U.S. Army soldier holding his M14 (or M21) rifle: as a gas-operated firearm, this weapon is capable of semi-automatic fire, with a much higher rate of fire than bolt-action designs

The choice between bolt-action and semi-automatic actions (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 has the following advantages:

  • Cheaper to build and maintain
  • More accurate, since there are fewer moving parts
  • Manual case ejection and bolt operation, allowing for greater discretion
  • Versatile fire-positioning, since there is no need for a large magazine
  • Reliable, with fewer components that may fail or become jammed
  • Lighter weight, once again due to fewer components

For semi-automatic actions, the following advantages are available:

  • Cross-purpose use as both a battle rifle and a sniper rifle
  • Greater volume of fire when needed in a suppressing support role
  • Faster follow-up shots due to higher rate of fire
  • Commonality of operation with issued service rifle, depending on system

A bolt-action is the 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 see a higher usage of 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 logistics 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.

A police semi-automatic sniper rifle may be used in a fast moving raid, or in a situation that requires the sniper to engage multiple targets in quick succession. These rifles tend to be used comparatively rarely due to the danger that a faster-firing semi-automatic may present to innocent bystanders. The flight time of the bullet, combined with the limited field of view of a sniper peering through a scope may allow an innocent victim to cross into a bullet's path, similar to what happened in the Ruby Ridge incident.

Cartridge

The cartridge determines nearly all of the other features and capabilities of a sniper rifle, and sets limitations on how it can be used. The following is a short list of only some of the issues that are affected by the caliber chosen:

  • Effective range
  • Ballistic peformance
  • Types of targets that can be effectively engaged
  • Cost, and consequently, the number of rifles purchased and employed

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 chambering instead of trying to break new ground with less-perfected (but possibly better) ammunition.

Before the introduction of the 7.62 × 51 mm NATO in the 1950s, standard military calibers utilized were the .30-06 Springfield (United States), .303 British (United Kingdom) and 7.92 × 57 mm (8 mm 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 7.62 × 51 mm. At the present time, in both the West and within NATO, 7.62 × 51 mm NATO (.308 Winchester) is currently the primary cartridge of choice for over 90% of military and police sniper rifles.[citation needed]

Worldwide, the trend is similar. The preferred sniper rifle in Russia is another .30 caliber military cartridge—the 7.62 × 54 mm R, which has similar performance to the 7.62 × 51 mm NATO. This cartridge was introduced in 1891, and both Russian sniper rifles of the modern era, the Mosin-Nagant and the Dragunov (SVD), are chambered for it.

Certain commercial cartridges designed without the logistical constraints of most armies and only performance in mind have also gained popularity in the 1990s—these include the .338 Lapua and .300 Winchester Magnum. These cartridges have offered better ballistic performance and a greater effective range than the 7.62 × 51 mm NATO. Though they are not as powerful as .50 caliber cartridges (e.g. the .50 BMG), they also do not suffer any weight penalty as is the case for rifles chambered for .50 caliber ammunition, and, as such, offer a significant improvement over rifles chambered for the 7.62 × 51 mm NATO.

 
M82A1 SASR (Special Applications Scoped Rifle), a high-powered .50 caliber sniper rifle used as a military anti-materiel rifle

Snipers (mostly military) also employ anti-materiel rifles in sniping roles against targets such as vehicles, equipment and structures, or for the long-range detonation of explosive devices. Although designed or employed primarily as anti-materiel rifles, they may also be used against personnel in certain situations.

These rifles tend to be semi-automatic, and of a larger caliber than anti-personnel rifles, using .50 caliber (12.7 mm, such as the .50 BMG and Raufoss Mk211) or even 20 mm cartridges. Due to their considerable size and weight, snipers operating in 2- or 3-man teams becomes a necessity.

Examples of anti-materiel military sniper rifles:

Barrel

Rifle barrels employed in sniper rifles 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 rifles and assault rifles, the bores are usually not chromed to avoid the potential of inaccuracy due to an uneven treatment.

When installed, barrels are often free-floated or installed so the barrel only contacts the rest of the rifle at the reciever to minimize the effects 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 damage and therefore innacuracy. Alternately, some rifles like the Russian SVD or Walther WA2000 create a reinforcing structure that provides a frame to counteract these pressures on the barrel.

Another trait sometimes seen with sniper barrels are external longitudinal fluting that contributes to heat dissipation by increasing surface area while simultaneously decreasing the weight of the barrel.

Sniper rifle barrels may also utilize a threaded muzzle or combination device (muzzle brake or flash hider and attachment mount) to allow the fitting of a sound suppressor, often with it's own means of adjusting the point of impact when fitted.

Military sniper rifles tend to have longer barrels of around 23.5 inches (600 mm) to allow the cartridge propellant to fully burn and get the highest bullet velocity. This also reduces muzzle flash, helping to keep the sniper concealed. Some police sniper rifles have shorter barrels to make them easier to handle. The shorter barrels' velocity loss is less important at closer range where velocities and projectile energy remain well over that needed to reliably perform as needed.

Stock

File:Usmc kabul DMR sighting.jpg
USMC DMR showing adjustable cheek piece.

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, it is necessary to have this area raised slightly, because the telescope is positioned higher than iron sights, and a rifle shooter should steady his cheek against a rifle while aiming. 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 fitment, the stock can sometimes also be adjusted for length, often by varying the number of butt pad inserts at the rear of the stock where it meets the shooter's shoulder.

A permanently fixed or removable bipod attached to the rifle's forearm is another non-standard, but important piece of equipment. It acts as a steady and level object on which to rest the rifle which aids in accuracy.

Other accessories

Sniper rifles often have specialised accessories, such as variable length gas-strut bipods.

Accurizing and maintenance

In the case of rifles designed specifically for sniping, the same procedures or techniques applied to any rifle to achieve long-range accuracy is used. Some of these techniques are described in the article on accurizing a firearm and may include the following:

  • A free-floating barrel, where the barrel is attached to the rifle at a single point, screwed into the action without touching the forearm—this prevents the barrel from being deflected when pressure is applied against the forearm.
  • Heavier barrels to increase the resonant frequency (again) and slow the rate of heating, which reduces thermal distortion of the barrel as more rounds are shot. This also increases the weight of the rifle, thus reducing the felt recoil.
  • Fluting on heavier barrels help maintain the desired characteristics of a heavy barrel, but reduces the weight of the barrel.
  • The end of the barrel may be counter-sunk a few millimetres to protect the critical exit-end of the rifling from damage.

When standard rifles are adapted for use as a sniper rifle common improvements on the action or internals include:

  • Polishing the trigger sear to improve the feel of the trigger pull and therefore the shooter's trigger control.
  • A low-mass (often titanium) hammer and firing pin reduce the time between the trigger pull and the primer ignition (called lock time). By reducing this time between the trigger being pulled and the bullet release, it reduces the distance that a human being's irreducible quiver can move the point of aim.

Capabilities

When examined individually, the capabilities of a sniper rifle may not seem unique, or even particularly extraordinary compared to other types of firearms. Certainly, on the face of it there is little to differentiate a specialist sniper rifle from a garden-variety scoped hunting rifle. However, the prima facie disadvantages of a sniper rifle, such as slow rate of fire, can become advantages, encouraging the shooter to take their time and make every shot count, for example.

When taken as a whole, the subtle advantages possessed by a sniper rifle can allow a sniper to dominate an enemy who possesses far greater fighting capability. However, since sniping is a specialized role, it must be noted that the success of a sniper depends more on the level of skills and training than on the particular rifle used.

Accuracy

 
Comparison of 0.5, 1, and 3 MOA accuracy levels against a human torso at 800 m (left) and a human head at 100 m (right)

Contrary to popular belief, sniper rifles are not necessarily characterized by exceptional accuracy—especially when compared to civilian sporting rifles—, though they nearly always match or exceed the capabilites of other types of rifles in the military and police categories[2].

The United States military standards call for only 1 MOA[3] accuracy from a standard issue sniper rifle[4], since accuracy is sacrificed in favor of low cost and reliability in harsh environments, as well as ease of operation and maintenance.

Although accuracy standards for police rifles do not widely exist, they are frequently seen with accuracy levels from 1.5 MOA to as high as 0.5 MOA[5] — and occasionally as high as .25 MOA in the most expensive models[6].

However, it is interesting to note that in the realm of police usage, average or even below average accuracy is usually all that is technically required[7]. This is because police typically employ their rifles at very short ranges[8] [9]. At 70 meters or less, nearly any inexpensive rifle with a relatively low accuracy of only 1 MOA should be able to repeatedly hit a 1 inch target. One inch is approximately the size of a man's thumb, which is smaller than the brain stem, the most prized target of a police sniper[10]. However, police agencies might sometimes prefer to buy rifles with capabilities that exceed technical requirements[11], in order to bolster their credibility under public scrutiny[12].

The following is a list of typical accuracies, for comparison:

  • A common pistol may be capable of between 15 MOA and 30 MOA accuracy
  • A military-issue battle rifle or assault rifle is usually capable of between 3 MOA and 6 MOA accuracy
  • Civilian or police semi-automatic rifles are typically capable of less than 1 MOA to 4 MOA accuracy
  • A common hunting rifle may be capable of 0.5 to 3 MOA accuracy
  • A standard-issue military sniper rifle is typically capable of 0.5 to 2 MOA accuracy
  • A police sniper rifle is typically capable of 0.25 to 1.5 MOA accuracy
  • A competition target rifle may be capable of accuracy levels of 0.1 MOA or higher
  • Rifles designed for scientific testing of ammunition may be so accurate that sophisticated computer equipment is required to measure their accuracy

Maximum effective range

Sniper rifles are sometimes characterized as having exceptionally great range capability compared to other small arms, but this is not necessarily true.

For example, police snipers usually employ their rifles at very short ranges, frequently under 50 meters, which is within the range of common pistols. In police sniping, not only is long range generally not required, but it is often undesirable, especially if there are innocent bystanders further beyond the intended target.

Unlike police sniper rifles, military sniper rifles tend to be employed at the greatest possible distances so that range advantages can be exploited. However, machine guns, battle rifles, counter-sniper rifles, designated marksman rifles, and sometimes even mass-fire from several assault rifles can reach or even greatly exceed the range of a sniper rifle.

The most popular military sniper rifles (in terms of the numbers in service) are chambered for some type .30 caliber ammunition[citation needed], such as 7.62 × 51 mm NATO (.308 Winchester), or similar. Since sniper rifles of this class must compete with several other types of military weapons with similar range, snipers invariably must employ skilled fieldcraft to conceal their exact positions, and avoid being killed.

The recent trend in specialized military sniper rifles is towards larger calibers that have greater range, such as .338 Lapua and .50 BMG. This allows snipers to take fewer risks, and spend less time finding concealment, when facing enemies that are not equipped with similar weapons.

Approximate maximum effective ranges of common ammunition when used in a sniper rifle (lower figures are typical, higher figures are under ideal conditions):

Cartridge Maximum effective range
5.56 × 45 mm NATO 400–600 m
.243 Winchester 600 m
7.62 × 51 mm NATO 800–1,000 m
.300 Winchester Magnum 900–1,100 m
.338 Lapua 1,200–1,500 m
.50 BMG 1,500–2,000 m or more

Range vs. accuracy

 
A 1 MOA sniper rifle's small 8-inch target circle at 800 m, and a single bullet strike
 
A 6 MOA machine gun's large 66-inch target circle at 1,100 m, and multiple bullet strikes

Sniper rifles are considered ineffective beyond the distance a carefully-fired shot is guaranteed to strike the target. At longer ranges, a miss could occur that might endanger the shooter's mission. In those instances, other small arms may be preferred over sniper rifles, even though the situation may otherwise be an ideal job for a sniper rifle.

For example, in counter-sniper roles a sniper might spot a target that is out of range for a sniper rifle, and so the sniper may need to call upon a machine gunner to attack it. A machine gun using the same ammunition as the sniper rifle can be effective at a much greater range due to lower accuracy requirements for effective use.

Here is a simplified example to illustrate why, counter-intuitively, a less accurate weapon of the same caliber may actually have a greater effective range than a sniper rifle:

For human targets in military sniping, snipers do not aim at the person, instead they aim at a target circle [13] on the person (see the illustrations in this section). The circle is typically about 8 inches in diameter, corresponding to an imaginary circle on the vital area of a man's chest. For a common sniper rifle capable of 1 MOA accuracy, the maximum effective range (the range at which the bullet impact point is guaranteed to be within an 8-inch circle on the first shot) is about 800 meters.

In contrast, a machine gun using the same ammunition with a low accuracy of only 6 MOA will typically have a greater maximum effective range of about 1,100 meters. At that range and accuracy, a machine gun can have a larger target circle of about 66 inches. The machine gun's target circle is much larger than the human target due to its rapid fire capability, which allows a machine gun to strike with 1 or more hits and numerous misses at random locations within the target circle.

While a machine gun's large target circle means that its range can be longer than a sniper rifle's [14], the corresponding disadvantage is that the machine gun may need to fire dozens, and perhaps hundreds of rounds before scoring a hit.

See also

References and notes

  1. ^ The Ultimate Sniper: an Advanced Training Manual for Military and Police Snipers, Major John Plaster, 1993. The information about counter-sniper operations describes techniques for identifying snipers amongst groups of other soldiers. The most easily recognizable feature of a sniper from a great distance is the fact that the sniper's rifle is longer than all the others.
  2. ^ Rifle accuracies mentioned here are typically measured in a real-world situation by a competent marksman, rather than by a machine. Accuracies measured by a marksman take into account not only the mechanical contributions of the barrel and action to accuracy, but also the kinematic behavior of things like the stock and the trigger in the whole rifle system. Accuracy as measured from a rigid machine is not considered to have useful real-world meaning in the precision rifle industry[citation needed] due to the fact that the movement of a rifle during the process of firing affects real-world shot placement. For example, two rifles that have the same accuracy as measured from a machine may be verifiably different when measured by a human: one rifle may move very consistently during firing, and is thus very accurate, while the other rifle may not. Note that the distance a rifle moves during firing is not as important to accuracy as the consistency with which it moves.
  3. ^ This level of accuracy roughly translates into a variance in the bullet's point of impact of 8 inches at 800 yards, which is considered sufficient to ensure a high probability of hitting a human shape at that distance.
  4. ^ "... all weapons must shoot less than one minute of angle (MOA)."[1]
  5. ^ The FBI, a national-level policing organization, has recently specified an accuracy level of .5 MOA for sniper rifles issued to their SWAT teams: Johnson, D: Precision Pair, Guns & Ammo, February 2005. [2]
  6. ^ Tactical Operations, Inc guarantees .25 MOA accuracy in some of their police rifles
  7. ^ "With tight budgets, some may question the need for this level of workmanship and accuracy. A 1 MOA capability has been considered to be adequate in the police sniper community. Certainly, 1 MOA is perfectly adequate for making reliable head shots at the ranges and under the conditions commonly encountered by the police sniper.", Tac OPS Tango 51: Shorter Barrel Defies Conventional Wisdom[3], Eugene Nielsen, The Tactical Edge, Fall 2000.
  8. ^ Minimum documented range is 5 yards, maximum documented range is 187 yards: Police Sniper Utilization Survey, American Sniper Association, 2006, full report available to military and law enforcement agencies only.[4][5]
  9. ^ Some information publicly available from The Ultimate Sniper: an Advanced Training Manual for Military and Police Snipers, Major John Plaster, 1993.
  10. ^ Police Sniper Training, Major John Plaster, 1990.[6]
  11. ^ Major John Plaster frequently criticizes the equipment choices of some police departments in his published writings training materials. See: The Ultimate Sniper: an Advanced Training Manual for Military and Police Snipers.
  12. ^ The Politics of Force: Media and the Construction of Police Brutality, Regina G. Lawrence, University of California Press, 1st edition, 02 October 2000, ISBN 0-520-22191-5
  13. ^ The equations that describe the approximate relationships between range, accuracy, and the target circle, as used in this section, are as follows:
    • Target circle inches X Accuracy MOA = Range meters
    • Range meters / Accuracy MOA = Target circle inches
    Also note that "target circle" is used exclusively even when "cone of fire" or "group size" may technically be more accurate. These terms have subtle differences that are not important for the purpose of this section, and they are left out to avoid introducing unnecessary complexity in illustrations and examples that have been intentionally simplified. See also: Ballistics, cone of fire, Accuracy and precision, and group size
  14. ^ Note that the design of a weapon is more likely to determine its effective range than the maximum range of its ammunition. The maximum range of common 7.62 × 51 mm NATO ammunition is a comparatively tremendous 3,725 meters, and both machine guns and sniper rifles are not able to use even half of the maximum range of the ammunition effectively, largely due to unpredictable atmospheric disturbance of the bullet flight path. The very large maximum range of the ammunition is tightly constrained by the much smaller maximum effective range of the rifle/ammunition combination. This is true for nearly all modern firearms.

Further reading

  • Tobias, Ronald (1981). They Shoot to Kill: A Psycho-History of Criminal Sniping. Boulder, Colorado: Paladin Press. ISBN 0-87364-207-4.
  • De Haas, Frank (1995). Bolt Action Rifles. Krause Publications. ISBN 0-87349-168-8.