Rifle

A rifle is any long gun which has a rifled barrel. A rifled barrel incorporates two or more helical grooves in its bore which impart a spin upon the projectile as it travels down the barrel. The angular momentum thereby imparted to the projectile partially insulates it from certain aerodynamic forces which would otherwise cause it to deviate more substantially from a straight path. The consequent gyroscopic stability allows for much greater accuracy, and therefore, effective range, than would otherwise be attainable through the use of a non-rifled barrel, such as that in a musket or shotgun.

Originally, rifles were sharpshooter weapons, whilst the regular infantry made use of the greater firepower of massed muskets, which fired round balls of calibres up to .60". Benjamin Robins, an English mathematician, realised that an extruded bullet would retain the mass and kinetic force of a musket ball, but would slice through the air with much greater ease. The innovative work of Robins and others would take until the end of the 1700s to gain acceptance.

By the mid-1800s, however, manufacturing had advanced sufficiently that the Brown Bess was replaced by a range of - generally single-shot, breech-loading - rifles, designed for aimed, discretionary fire by individual soldiers. Then as now, rifles have a stock, either fixed or folding, which is braced against the shoulder. Until the early 1900s rifles tended to be very long - a Martini-Henry of 1890 was almost six feet in length, with a fixed bayonet - and the demand for more compact weapons for cavalrymen led to the 'carbine', or shortened rifle.

Most rifles are firearms - powered by gunpowder - although some of the earliest rifled weapons were powered with compressed air. Air rifles remain popular today, for plinking and hunting small game.

Some manufacturers make rifled shotguns, or rifled chokes for shotguns, which are designed to fire large lead slugs. Although these weapons are no different from 18th century rifles, they are nonetheless still referred to as shotguns, as they are quite rare. Artillery and tank cannon barrels are often rifled but, being crew-served weapons over a certain length, they are not referred to as "rifles", but are, in fact, referred to, in the proper sense of the word, as "guns".

History

History of design

Muskets were smooth-bore, large caliber weapons using ball-shaped ammunition fired at relatively low velocity. Because of the high cost and great difficulty of precision manufacturing, the ammunition generally did not fit tightly in the barrel. The origins of rifling are difficult to trace, but some of the earliest practical experiments seem to have originated in Europe during the fifteenth century. Archers had long realised that a twist added to the tail feathers of their arrows gave them greater accuracy. Early muskets produced large quantities of smoke and soot, which had to be cleaned from the action and bore of the musket frequently; either the action of repeated bore scrubbing, or a deliberate attempt to create 'soot grooves' might also have led to a perceived increase in accuracy, although no-one knows for sure. True rifling dates from the mid-1400s, although the precision required for its effective manufacture kept it out of the hands of infantrymen for another three and a half centuries.

Some early rifles were created with special barrels that had a twisted polygonal shape. Specially-made bullets were designed to match the shape so the bullet would grip the rifle bore and begin to spin. They generally remained large caliber weapons and the ammunition still did not fit tightly in the barrel. Many experimental designs used different shapes and degrees of spiralling. Although uncommon, polygonal rifling remains today; the popular Glock pistols have polygonal rifling, for example.

These designs were gradually replaced with cylindrical barrels cut with helical grooves, the surfaces between the grooves being called "lands". This innovation shortly preceded the mass adoption of breech-loading weapons, as it was not practical to push an overbore bullet down through a rifled barrel. Several systems were tried to deal with the problem, usually by resorting to an underbore bullet that expanded upon firing. One of the most famous was the Minié system, which relied on a conical bullet (known as a Minie bullet or Minié ball) with a hollow at the base that would expand and grip the rifling as the round was fired. Minié system rifles, notably the U.S. Springfield and the British Enfield of the early 1860s, featured prominently in the U.S. Civil War.

As the bullet enters the barrel it screws itself into the rifling, a process which gradually wears down the barrel, and more rapidly causes the barrel to heat up. For this reason machine-guns are equipped with quick-change barrels which can be swapped every few hundred rounds. Hardened armour-piercing bullets produce wear rapidly, which necessitates that they are encased in softer metal or teflon. Many modern bullets are coated with copper for the same reason.

Over the 19th century, bullet design also evolved, the slugs becoming gradually smaller and lighter. By 1910 the standard blunt-nosed bullet had been replaced with the pointed, 'spitzer' slug, an innovation which increased range and penetration. Cartridge design evolved from simple paper tubes containing black powder and shot to sealed brass cases with integral primers for ignition, whilst black powder itself was replaced with cordite and other smokeless mixtures, propelling bullets to higher velocities than before.

Rifles were initially single-shot, muzzle-loading weapons. During the 18th century, breech-loading weapons were designed, which allowed the rifleman to reload whilst under cover, but defects in manufacturing and the difficulty in forming a reliable gas-tight seal prevented widespread adoption. During the 19th century, multi-shot repeating rifles using lever, pump or linear bolt-actions became standard, further increasing the rate of fire and minimising the fuss involved in loading a firearm. The problem of proper seal creation had been solved with the use of brass cartridge cases, which expanded upon firing and effectively sealed the breech. By the end of the 19th century, the leading bolt-action design was that of Paul Mauser, whose action - wedded to a reliable design possessing a five-shot magazine - became a world standard through two world wars and beyond. The Mauser rifle was paralleled by Britain's ten-shot Lee-Enfield and America's 1903 Springfield rifle models, the latter of which is pictured above.

The advent of mass, rapid firepower and of the machine-gun and the rifled artillery piece was so rapid as to outstrip the development of any way to attack a trench filled with rifle and machine-gun equipped soldiers. The nightmare hell of the Great War was to be the greatest vindication and vilification of the rifle as a military weapon. By the Second World War military thought was turning elsewhere, towards more compact weapons. These designs became the assault rifle, one of the most significant technical developments of the 20th century in any field.

Nonetheless, civilian rifle design has not significantly advanced since the early part of the 20th century. Modern hunting rifles have fiberglass stocks and more advanced recoil pads, but are fundamentally the same as infantry rifles from 1910. Many modern sniper rifles can trace their ancestry back for over a centry; the Russian 7.63x54mm bullet, used in the front-line SVD Dragunov, dates from 1891.

WW2 saw the first mass-fielding of self-loading, semi-automatic rifles including the M1 Garand. As machine-gun mechanisms became smaller, lighter and more reliable, fully-automatic rifles and assault rifles became the norm.

History of use

Muskets were used for rapid, unaimed volley fire. The rifle was originally a sharp-shooter's weapon used for targets of opportunity and sniper fire. In the early part of the 20th century, soldiers were trained to shoot accurately over long ranges with high-powered cartridges. WW1 Lee-Enfields and several other rifles were equipped with long-range 'volley sights' for massed fire at ranges of up to a mile - individual shots were unlikely to hit, but a platoon firing repeatedly could produce an effect similar to artillery - but experience in WW1 showed that long-range fire was best left to artillery and machine guns.

Up to, during, and after WW2 it has become accepted that most infantry engagements took place at ranges of less than 100 metres, and that the range of power of old military rifles was 'overkill'. Today, an infantryman's rifle is optimised for ranges of 300 meters or less, and soldiers are trained to deliver individual rounds or bursts of fire at these ranges.

Accurate, long-range fire is the domain of the sniper and of enthusiastic target shooters. The modern sniper rifle is generally capable of accuracy greatly below that of one minute of angle. The most interesting recent development in this field has been the large-calibre sniper rifle, typically firing a bullet of .50", although other calibres are available. The Barrett M82A1 is probably the most common 0.50" sniper rifle, although it is used mainly as an anti-material weapon. This is because the 0.50" calibre is considered "too crude" for surgical shots. Many snipers still hold the claim that a 7.62mm calibre bolt-action rifle is the only true "sniper rifle", although semi-automatic sniper rifles such as the KAC SR25 have increased in popularity.

Derived from experiments with inter-war anti-tank rifles, modern large-calibre designs gained acceptance in the 1980s as a means of destroying equipment and personnel at distances of a mile or more, thus allowing snipers greater stand-off than before. The longest ranges possible with rifled weapons are however produced with artillery pieces, a typical 155mm NATO howitzer being capable of hitting an area at a distance of up to 30 kilometres, depending on the ammunition.

See also: assault rifle, sniper, firearm action, Mauser, Winchester rifle, Springfield rifle, Martini-Henry, Lee-Enfield, Sharps, Colt, Marlin rifle, pistol, carbine, bayonet, Baker rifle, Brunswick rifle, musket, M1 Garand, M1 Carbine, sniper rifle, bullpup rifle, repeating rifle