Sniper rifle Type And Design
In
military and
law enforcement terminology, a
sniper rifle is a precision-
rifle used to ensure more accurate placement of bullets at longer ranges than other
small arms. It is a common misconception that any scoped rifle is a
sniper rifle, and while certain
long guns are more suited for the application than others, it is the act of using a weapon strategically as a
sniper that designates it as such. A typical sniper rifle is built for optimal levels of
accuracy, fitted with a
telescopic sight and chambered for a military
centerfire 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, although "sniping rifle" or "sniper's rifle" is the technically
correct term for such a rifle.
The military role of a
sniper (a term derived from the
snipe,
a bird which was difficult to hunt and shoot) dates back to the turn of
the 18th century, but the true 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 enable them to deliver precise shots
over greater distances than regular
infantry weapons. The rifle itself could be based on a standard rifle (at first, a
bolt-action rifle); however, when fitted with a telescopic sight, it becomes a sniper rifle.
Contents
- 1 History
- 2 Classification
- 2.1 Military
- 2.2 Law enforcement
- 3 Distinguishing characteristics
- 3.1 Telescopic sight
- 3.2 Action
- 3.3 Cartridge
- 3.4 Barrel
- 3.5 Stock
- 3.6 Accessories
- 4 Capabilities
- 4.1 Accuracy
- 4.2 Maximum effective range
- 5 See also
- 6 Notes
- 7 References
- 8 External links
History
The Whitworth rifle was arguably the first long-range sniper rifle in the world.
[1] Designed by Sir
Joseph Whitworth, a prominent British engineer, it used twisted
hexagonal
barrels instead of traditional round rifled barrels, which meant that
the projectile did not have to bite into grooves as was done with
conventional rifling. His rifle was far more accurate than the
Pattern 1853 Enfield, which had shown some weaknesses during the recent
Crimean War.
At trials in 1857 which tested the accuracy and range of both weapons,
Whitworth's design outperformed the Enfield at a rate of about three to
one. The Whitworth rifle was able to hit the target at a range of 2,000
yards, whereas the Enfield could only manage it at a distance of 1,400
yards.
[2]
During the
Crimean War,
the first optical sights were designed for fitting onto the rifles.
Much of this pioneering work was the brainchild of Colonel D. Davidson,
using optical sights produced by
Chance Brothers of
Birmingham. This allowed a
marksman to more accurately observe and target objects at a greater distance than ever before.
[3]
The telescopic sight, or scope, was originally fixed and could not be
adjusted, which therefore limited its range. By the 1870s, the
perfection of
breech loading magazine rifles led to sniper rifles having “effective accurate” ranges of up to a mile away from its target.
[4]
During the
Boer War, the latest
breech-loading rifled guns with
magazines and
smokeless powder were used by both sides. The British were equipped with the
Lee-Metford rifle, while the Boers had received the latest
Mauser rifles from Germany. In the open terrain of
South Africa the marksman was a crucial component in battle. The
Lovat Scouts was a British Army unit formed in 1899 who were renowned for their expert marksmanship and their stalking skills. They wore
ghillie suits for camouflage and were expertly skilled in observation.
Hesketh Hesketh-Prichard said of them that "keener men never lived".
[5] After the Boer War the Scouts became the first official sniper unit in the
British Army.
It was not until
World War I,
that sniper rifles began to be used more regularly in battle and
certain soldiers given specialized training to use such a rifle. In
Germany these trained
snipers were given rifles with telescopic sights, which illuminated at night in order to improve their accuracy.
[6] German
gunsmiths fitted the scope above the barrel for optimal accuracy.
[7]
During the War, the accuracy of the sniper rifle was greatly improved.
[8] By the end of
World War II snipers were reported to provide “reasonable accuracy” over 600 m (656 yd) with anything over this range being unpredictable.
[9]
It was during World War I and II that the word ‘sniper’ began to be
used commonly, whereas previously those who were armed with sniper
rifles were referred to as sharpshooters, or marksmen.
[10]
These marksmen, wielding sniper rifles, had a drastic and demoralizing effect on the battlefield.
[11] Soldiers would often remain hidden in
foxholes, or
trenches
so as not to expose themselves to the deadly accuracy of a sniper. Some
soldiers even began to disregard orders from commanding officers to
protect against potential harm, which thus broke down the
chain of command on the battlefield.
[12] The sniper rifle soon acquired the reputation of being one of the most effective and ruthless weapons of war.
[13]
Though sniper rifles had proved to be extremely effective in combat,
there was still a great reluctance for many militaries to adopt a
trained sniper
regiment.
[14]
To effectively use a sniper rifle a soldier had to go through
particularly rigorous training, and most people did not make it past the
first week.
[15]
Sniper training was so expensive to conduct that even until as recently
as 1970, the reasoning for having trained snipers as a part of an army
was deemed questionable.
[14]
In Britain, sniper rifles were not seen as being an integral part of an
army until after the Germans boasted so much success with sniper teams
during the early months of World War I. The British army advisors
supposed that the telescopic sights attached to sniper rifles were too
easily damaged and thus not well suited for military use.
[9]
However, they soon realized that these telescopic sights could be
improved and made sturdy enough to withstand a sniper rifle shot.
[9]
Vietnam War era sniper rifles, US Army
XM21 (top) and USMC
M40 (bottom).
Sniper rifles have continued to be used consistently throughout the
later part of the 20th century in Korea, Vietnam and the Middle East as
an integral part of the modern style of
guerilla warfare.
The durability, accuracy and power of modern sniper rifles are beyond
anything in use even 10 years ago and would seem amazing in comparison
to any World War II sniper rifles.
[16]
Now sniper rifles are extremely reliable and are able to fire
repeatedly without losing accuracy, whereas earlier sniper rifles would
lose accuracy the more consistently they were used due to
wear and tear.
[17]
Sniper rifles continue to be adapted and improved upon with the
effective range of modern sniper rifles exceeding 1,000 m (1,094 yd),
which make it one of the most accurate, deadly and efficient weapons in
use now.
[17]
Classification
Modern sniper rifles can be divided into two basic classes:
military and
law enforcement.
Military
Sniper rifles manufactured for military service are often designed
for very high durability, range, reliability, sturdiness, serviceability
and repairability under adverse environmental and combat conditions, at
the sacrifice of a small degree of accuracy. Military snipers and
sharpshooters may also be required to carry their rifles and other
equipment for long distances, making it important to minimize weight.
Military organizations often operate under strict budget constraints,
which influences the type and quality of sniper rifles they purchase.
Law enforcement
Sniper rifles built or modified for use in law enforcement are
generally required to have the greatest possible accuracy, but do not
need to have as long a range.
Law enforcement-specific rifles are usually used in non-combat (often
urban) environments, so they do not have the requirement to be as hardy
or portable as military versions; therefore, they may be smaller,
because they do not need very long range.
Some of the first sniper rifles designed specifically to meet police and other law-enforcement requirements were developed for
West German police after the
Munich massacre at the
1972 Summer Olympics. Many police services and law enforcement organizations (such as the
U.S. Secret Service) now use rifles designed for law enforcement purposes.
The
Heckler & Koch PSG1
is one rifle specifically 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 was built for, and is marketed to, law enforcement rather than military agencies.
Distinguishing characteristics
Looking through a telescopic sight.
PSO-1 Sniper Scope Reticle
1 - Lead/deflection scale
2 - Main targeting chevron
3 - Bullet drop chevrons
4 - Rangefinder
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,
[18] a stock designed for firing from a
prone position, and the presence of a
bipod and other accessories.
Telescopic sight
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 4× and
up to 40×), 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 known as
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 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 Marine manually extracts an empty cartridge and chambers a new 7.62×51mm 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.
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 and
match grade
ammunition. 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
7.62×51mm NATO (.308 Winchester) cartridge in the 1950s, standard military cartridges were the
.30-06 Springfield or 7.62×63mm (United States),
.303 British (7.7×56mmR) (United Kingdom) and
7.92×57mm (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 7.62×51mm. At the present time, in both the
Western world and within
NATO,
7.62×51mm 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 caliber military cartridge, the
7.62×54 mm R,
which has similar performance to the 7.62×51mm. 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 (7.2×64mm),
.300 Winchester Magnum (7.8/7.62×67mm), and the
.338 Lapua Magnum
(8.6×70mm). These cartridges offer better ballistic performance and
greater effective range than the 7.62×51mm. Though they are not as
powerful as .50 caliber cartridges, rifles chambered for these
cartridges are not as heavy as rifles chambered for .50 caliber
ammunition, and are significantly more powerful than rifles chambered
for 7.62×51mm.
M82A1 SASR (Special Applications Scoped Rifle or Semi-Automatic Sniper Rifle), a .50 caliber 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 caliber than anti-personnel rifles, using cartridges such as the
.50 BMG,
12.7×108mm Russian or even
14.5×114mm Russian and
20mm.
These large cartridges are required to be able to fire projectiles
containing payloads such as explosives, armor 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 that 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 a means of adjusting the point of impact while fitted.
Military sniper rifles tend to have barrel lengths of 609.6 mm
(24 inches) or longer, to allow the cartridge propellant to fully burn,
reducing the amount of revealing muzzle flash and increasing muzzle
velocity. Police sniper rifles may use shorter barrels to improve
handling characteristics. The shorter barrels' muzzle velocity loss is
unimportant at closer ranges; the impact velocity of the bullet is more
than sufficient.
Stock
H-S Precision Pro Series 2000 HTR sniper rifle with adjustable stock and accessories rails.
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 his non-firing arm into the sling forcing his
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.
Capabilities
Accuracy
Comparison of 0.5, 1, and 3
MOA extreme spread levels against a human torso at 800 m (left) and a human head at 100 m (right)
A military-issue
battle rifle or
assault rifle is usually capable of between 3-6
minute of angle (
MOA) (1-2
mrad) accuracy.
[19]
A standard-issue military sniper rifle is typically capable of 1-3 MOA
(0.3-1 mrad) accuracy, with a police sniper rifle capable of 0.25-1.5
MOA (0.1-0.5 mrad) accuracy. For comparison, a competition target or
benchrest rifle may be capable of accuracy up to 0.15-0.3 MOA (0.05-0.1 mrad).
A 1 MOA (0.3 mrad) average extreme spread for a 5-shot group (meaning
the center-to-center distance between the two most distant bullet holes
in a shot-group) translates into a 69% probability that the bullet's
point of impact will be in a target circle with a diameter of 23.3 cm
(9.2 in) at 800 m (875 yd).
[20]
This average extreme spread for a 5-shot group and the accompanying hit
probability are considered sufficient for effectively hitting a human
shape at 800 m distance.
In 1982 a U.S. Army draft requirement for a Sniper Weapon System was:
"The System will: (6) Have an accuracy of no more than 0.75 MOA (0.2
mrad) for a 5-shot group at 1,500 meters when fired from a supported,
non-benchrest position".
[21] Actual Sniper Weapon System (
M24)
adopted in 1988 has stated maximum effective range of 800 meters and a
maximum allowed average mean radius (AMR) of 1.9 inches at 300 yards
from a machine rest, what corresponds to a 0.6 MOA (0.5 mrad) extreme
spread for a 5-shot group when using 7.62 × 51 mm M118 Special Ball
cartridges.
[22][23][24]
Precision Weapon Engagement Ranges & Dispersion according to the US Army.
A 2008
United States military market survey for a
Precision Sniper Rifle
(PSR) calls for 1 MOA (0.3 mrad) extreme vertical spread for all shots
in a 5-round group fired at targets at 300, 600, 900, 1,200 and 1,500
meters.
[25][26] In 2009 a
United States Special Operations Command
market survey calls for 1 MOA (0.3 mrad) extreme vertical spread for
all shots in a 10-round group fired at targets at 300, 600, 900, 1,200
and 1,500 meters.
[27][28]
The 2009 Precession Sniper Rifle requirements state that the PSR when
fired without suppressor shall provide a confidence factor of 80% that
the weapon and ammunition combination is capable of holding 1 MOA
extreme vertical spread. This shall be calculated from 150 ten (10)
round groups that were fired unsuppressed. No individual group shall
exceed 1.5 MOA (0.5 mrad) extreme vertical spread. All accuracy will be
taken at the 1,500 meter point.
[29][30] In 2008 the US military adopted the
M110 Semi-Automatic Sniper System
which has corresponding maximum allowed extreme spread of 1.8 MOA (0.5
mrad) for a 5-shot group on 300 feet, using M118LR ammunition or
equivalent.
[22][23][31] In 2010 the maximum bullet dispersion requirement for the
M24 .300 Winchester Magnum corresponds
[22][23] to 1.4
MOA extreme spread for 5 shot group on 100 meters.
[32]
Although accuracy standards for police rifles do not widely exist,
rifles are frequently seen with accuracy levels from 0.5-1.5 MOA
(0.2-0.5 mrad).
[33]
For typical policing situations, an extreme spread accuracy level no
better than 1 MOA (0.3 mrad) is usually all that is required. This is
because police typically employ their rifles at short ranges.
[34]
At 100 m or less, a rifle with a relatively low accuracy of only 1 MOA
(0.3 mrad) should be able to repeatedly hit a 3 cm (1.2 inch) target. A
3 cm diameter target is smaller than the
brain stem which is targeted by police snipers for its quick killing effect.
[35]
Maximum effective range
Cartridge |
Maximum effective range[36] |
7.62×39mm |
600 m |
5.56×45mm |
600 m [37] |
7.62×51mm (.308 Winchester) |
800 m |
7.62×54mm R |
800 m |
.30-06 Springfield |
800 m |
7 mm Remington Magnum |
900–1,100 m |
.300 Winchester Magnum |
900–1,200 m |
.338 Lapua Magnum |
1,200-1,500 m |
.50 BMG (12.7×99mm NATO)
12.7×108mm (Russian) |
1,500–2,000 m |
14.5×114mm |
1,800–2,300 m |
Unlike police sniper rifles, military sniper rifles tend to be
employed at the greatest possible distances so that range advantages
like the increased difficulty to spot and engage the sniper can be
exploited.
The most popular military sniper rifles (in terms of numbers in
service) are chambered for 7.62 mm (0.30 inch) caliber ammunition, such
as
7.62×51mm and
7.62×54mm R.
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 position.
The recent trend in specialized military sniper rifles is towards
larger calibers that offer relatively favorable hit probabilities at
greater range, such as the anti-personnel
.338 Lapua Magnum cartridge and anti-materiel cartridges like the
.50 BMG and the
14.5×114mm.
This allows snipers to take fewer risks, and spend less time finding
concealment when facing enemies that are not equipped with similar
weapons.
Maximum range claims made by military organizations and materiel
manufacturers regarding sniper weapon systems are not based on
consistent or strictly scientific criteria. The problem is only the
bullet interacts after a relatively long flight path with the target
(can also be a materiel target for a sniper bullet). This implies that
variables such as the minimal required hit probability, local
atmospheric conditions, properties and velocity of the employed bullet
(parts), properties of the target and the desired terminal effect are
major relevant factors that determine the maximum effective range of the
employed system.