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Rifle

Rifle

A rifle is a firearm that uses a spiral groove cut into the barrel to spin a projectile (usually a bullet), thus improving accuracy and range of the projectile. It is the same principle that causes an American football to be more accurate when thrown correctly. Examples of non-rifled firearms are shotguns and muskets. muskets]

Overview

Originally, rifles were sharpshooter weapons, while the regular infantry made use of the greater firepower of massed muskets, which fired round balls of calibers up to 0.75 inch (19 mm). Benjamin Robins, an English mathematician, realized 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-19th century, 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 20th century rifles tended to be very long—a Martini-Henry of 1890 was almost six feet (1.8 m) in length, with a fixed bayonet—and the demand for more compact weapons for cavalrymen led to the carbine, or shortened rifle. A rifle is a type of firearm. Typicaly, the bullet is propelled by the contained detonation of an explosive compound (usually cordite), although other means are used, such as compressed air. Such rifles are called Air rifles, and remain popular for vermin control, hunting small game and casual shooting ("plinking") Some manufacturers make rifled shotguns.

History

History of design

Muskets were smooth-bore, large caliber weapons using ball-shaped ammunition fired at relatively low velocity. Due to the high cost and great difficulty of precision manufacturing, and the need to load readily from the muzzle, the musket ball was a loose fit in the barrel. Consequently on firing the ball bounced off the sides of the barrel when fired and the final direction on leaving the muzzle was unpredictable. 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 realized 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 rifled guns 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 take a spin that way. These were generally limited to large caliber weapons and the ammunition still did not fit tightly in the barrel. Many experimental designs used different shapes and degrees of spiraling. Although uncommon, polygonal rifling is still used in some weapons today with one example being the GLOCK line of pistols. 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, only to then (try to) fire it back out. The dirt and grime from prior shots was pushed down ahead of a tight bullet or ball (which may have been a loose fit in the clean barrel before the first shot), and, of course, loading was far more difficult, as the lead had to be deformed to go down in the first place, reducing the accuracy due to nose deformation. Several systems were tried to deal with the problem, usually by resorting to an under-bore bullet that expanded upon firing. One of the most famous was the Minié system, which relied on a conical bullet (known as a Minié ball) with a hollow at the base of the bullet that caused the base of the round to expand from the pressure of the exploding charge 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, due to the enhanced power and accuracy. The better seal gave more power, as less gas escaped past the bullet, which combined with the fact that for the same bore (caliber) diameter a long bullet was heavier than a round ball. Enhanced accuracy came from the expansion to grip the rifling, which spun the bullet more consistently. Another important area of development was the way rounds were stored and used in the weapon. The Spencer repeating rifle was a breech-loading manually operated lever action rifle, that was adopted by the United States and over 20,000 were used during the Civil War. It marked the first adoption of a removable magazine-fed infantry rifle by any country. The design was completed by Christopher Spencer in 1860. It used copper rim-fire cartridges stored in a removable seven round tube magazine, enabling the rounds to be fired one after another, and which, when emptied could be exchanged for another. 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 thousand rounds, or, in earlier designs, were water-cooled. Modern stainless steel barrels for target rifles are much harder, and so wear far less, allowing tens of thousands of rounds to be fired before accuracy drops, unlike older carbon steel barrels, which were more limited, to around 1,000 shots, before the extreme accuracy faded. (Many shotguns and small arms have chrome-lined barrels to reduce wear and enhance corrosion resistance. This is rare on rifles designed for extreme accuracy as the plating process is difficult and liable to reduce the effect of the rifling.) Hardened armor-piercing bullets produce wear rapidly, which necessitates that they are encased in softer metal or Teflon. 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 then other smokeless mixtures, propelling bullets to higher velocities than before. The increased velocity meant that new problems arrived, and so bullets went from being soft lead to harder lead, then to copper jacketed, in order to better engage the spiraled grooves without being "stripped" in the same way as a thread would be if subjected to extreme forces. 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 minimizing 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 at the point of firing and effectively sealed the breech while the pressure remained high, then shrinking back slightly to allow for easy removal. 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 pictured above), both of which were copied from Mauser's origninal design. 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. Experience in World War One led German military researchers to conclude long-range aimed fire was less significant at typical battle ranges of 500m. As mechanisms became smaller, lighter and more reliable, semi-automatic rifles rifles, including the M1 Garand, appeared. WW2 saw the first mass-fielding of such rifles, which culminated in the Walther MKb-42, the first assault rifle, one of the most significant developments of the 20th century army. By contrast, 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 century; the Russian 7.62 x 54 mm cartridge, used in the front-line SVD Dragunov, dates from 1891.

History of use

Muskets were used for rapid, unaimed volley fire. The average conscripted soldier could be easily trained to use them. The (muzzle-loaded) rifle was originally a sharpshooter's weapon used for targets of opportunity and sniper fire. The adoption of cartridges and breech-loading in the 19th century was concurrent with general adoption of rifles. In the early part of the 20th century, soldiers were trained to shoot accurately over long ranges with high-powered cartridges. World War 1 Lee-Enfields rifles (among others) were equipped with long-range 'volley sights' for massed fire at ranges of up to a mile (1600 m) - individual shots were unlikely to hit, but a platoon firing repeatedly could produce an effect similar to light artillery or a machine gun - 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 500 meters; the range and power of the large rifles was 'overkill'; and the weapons were heavier than the ideal. This led to Germany's development of the 7.92x39mm Kurz (short) round, the MKb-42, and ultimately, the assault rifle. 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 better than one arcminute (300 μrad). In recent decades large-caliber anti-material sniper rifles, typically around .50 (12.7 mm) caliber cartridges, have been developed. The US Barrett M82A1 is probably the best known such rifle. These weapons are typically used to strike critical, vulnerable targets such as radar antennae or the jet engines of enemy aircraft. Anti-materiel rifles can certainly be used against human targets, but the much higher weight of rifle and ammunition, and the massive recoil and muzzle blast, make them impractical for such use. The Barrett M82 is credited with a maximum effective range of 1800 meters (1.1 mile).

External links

- [http://www.nazarian.no/wepc.asp?lang=0&group_id=3 Nazarian`s Gun`s Recognition Guide on Bolt Action Rifles]
- [http://www.nazarian.no/wepc.asp?lang=0&group_id=5 Nazarian`s Gun`s Recognition Guide on Automatic Rifles]
- [http://www.self-defender.net/weapons/rifles.htm Modern Civilian And Military Rifles] Category:Rifles ja:小銃 ko:소총

Firearm

A firearm is a kinetic energy mechanical device that fires either single or multiple projectiles propelled at high velocity by the gases produced through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration. In older firearms, this propellant was typically black powder, but modern firearms use smokeless powder or other propellants. The term gun is often used as a synonym for firearm, but in specialist use has a restricted sense—referring only to an artillery piece with a relatively high muzzle velocity and a relatively flat trajectory, such as a field gun, a tank gun, an anti-tank gun, or a naval gun. Guns are distinct from howitzers and mortars, which have lower muzzle velocities and higher trajectories. Hand-held firearms, like rifles, carbines, pistols and other small firearms are never called "guns" in the restricted sense. In recent centuries, firearms have become the predominant weapons used by mankind. Modern warfare since the late Renaissance has relied upon firearms, with wide-ranging effects on military history and history in general. For handguns and long guns, the projectile is a bullet or, in historical cannons, a cannonball. The projectile is fired by the burning of the propellant, but in small arms rarely contains explosives itself. For modern artillery the projectile is a shell, which nearly always contains explosives. A distinction is sometimes made between the projectile itself as the weapon and the firearm as a weapons platform. In some cases, the firearm can be used directly as a weapon without firing a projectile, although this is generally a secondary method of attack. For example, arms such as rifles, muskets, and occasionally submachine guns can have bayonets affixed to them, becoming in effect a spear or pike. With some notable exceptions, the stock of a long gun can be used as a club. It is also possible to strike someone with the barrel of a handgun or grasp it by the barrel and strike someone with the butt. This is called "pistol-whipping". A problem for firearms is the accumulation of waste products from the partial combustion of propellants, metallic residue from the bullet itself, and small flecks of the cartridge case. These waste products can interfere with the internal functions of the firearm. As a result, regularly used firearms must be periodically partially disassembled, cleaned and lubricated to ensure the weapon's reliability. There are two basic categories of firearms: artillery pieces and small arms. Small arms are generally small, very portable firearms with a barrel bore of up to approximately 0.50 inch (12.7 mm)and are aimed visually at their targets using sights. The range of accuracy for small arms is limited to about one mile (1600 m), usually considerably less. Artillery pieces are much larger, mounted on a movable carriage, having bores of up to 18 inches (46 cm) and possibly weighing many tons. Artillery can be accurate at ranges of up to about 26 miles (42 km) and, with some notable exceptions (e.g., tank guns), is aimed using altitude/azimuth settings. Strictly speaking, not all small arms are firearms, but it is the most convenient category under which to group them.

Small arms

Handguns

The smallest of all small arms is the handgun (or "sidearm"). Handguns with a single, fixed firing chamber are pistols; most pistols have a removable magazine so they can be used to fire several shots. The other most common handgun design is the revolver, which has a number of firing chambers in a revolving cylinder; each chamber in the cylinder is loaded with a single cartridge. Prior to the 19th century, all handguns were single-shot muzzleloaders. With the invention of the revolver in 1818, handguns capable of holding multiple rounds became popular. At the end of the 20th century, most handguns are semiautomatic, although revolvers are still widely used. Handguns come in many shapes and sizes. For example, the "derringer" (a generic term based on the mid-19th-century "Deringer" brand name) is a very small, short-barreled handgun, usually with one or two barrels but sometimes more (some 19th-century derringers had four barrels) that have to be manually reloaded after being fired. Carefully matched single-shot duelling pistols were used primarily in the 18th and 19th centuries to settle serious differences among "gentlemen": Alexander Hamilton and Aaron Burr are probably the most prominent Americans who used duelling pistols to settle their differences. Fully automatic, relatively easily concealed machine pistols, such as the MAC-10 and the Beretta 93R, were a late 20th-century development. Handguns are small and usually made to be easily concealed, thus making them a very common choice for personal protection. In the military, handguns are usually issued to those who are not expected to need more potent (and more expensive) weapons, such as general and staff officers, and to those for whom there is no room for a full-sized rifle, such as armored vehicle and air crews. In this last role, they often compete with the carbine, which is also usually issued to airborne infantry because of its small size. Outside the military, handguns are the usual armament for police (in those jurisdictions where police are armed) and, where legal, for private citizens. Private citizens in most jurisdictions usually carry only concealed handguns in public except when hunting, since an unconcealed weapon would attract undue attention, and would therefore be less secure, athough there are significant numbers of states in the US that continue to permit open carry of handguns. In the United States, the number of states which permit concealed carry has recently grown to over 35, and several states have well over 200,000 permit holders. Despite Second Amendment constitutional roots in the United States, the concept of citizens carrying a concealed weapon for self-defense is often a contentious political issue; see gun politics for more information. Handguns are also used for many sporting purposes and hunting, although hunting usage is usually viewed as somewhat atypical due to the limited range and accuracy of handguns. Some hunters however relish the increased challenge involved in handgun hunting due to the necessity of approaching the game animal more closely. Small-bore (e.g., .22 caliber) handguns have long been very popular for competitive target shooting, partially due to the low cost of both the weapons and the ammunition, and there is also a rapidly growing number of sporting competitions for larger calibers.

Long guns

Most modern long guns are either rifles or shotguns. Historically, a long smoothbore firearm was known as a musket. A rifle has a rifled barrel that fires single bullets, while a shotgun fires packets of shot, a single slug, a sabot, or a specialty round (tear gas, Bolo Shell, lead powder, etc.). Rifles are often built for accuracy and long range and are aimed, while shotguns are usually designed to quickly hit a moving target and are instead "pointed". Rifles have a very small impact area but a long range and high accuracy. Shotguns have a large impact area with considerably less range and accuracy. However, the larger impact area can compensate for reduced accuracy, since shot spreads during flight; consequently, in hunting, shotguns are used for flying game. Rifles and shotguns are commonly used for hunting and often to defend a home or place of business. Usually, large game are hunted with rifles (although shotguns can be used—deer hunting with a shotgun is possible with the use of buckshot, sabots or slugs) while birds are hunted with shotguns. Shotguns are sometimes preferred for defending a home or business due to their wide impact area, shorter range, and reduced penetration of walls, which significantly reduces the likelihood of unintended harm, although the handgun is also commonly preferred. Rifles have been in nationally featured marksmanship events in Europe and the United States since at least the 18th century, when rifles were first becoming widely available—one of the earliest purely "American" rifle-shooting competitions took place in 1775, when Daniel Morgan was recruiting sharpshooters in Virginia for the impending war with England. In some countries, rifle marksmanship is still a matter of national pride. Some specialized rifles in the larger calibers are claimed to have an accurate range of up to about one mile, although most have considerably less range. In the second half of the 20th century, competitive shotgun sports became perhaps even more popular than riflery, largely due to the motion and immediate feedback in activities such as skeet, trap and sporting clays.

Machine guns

A machine gun is a fully automatic firearm used almost exclusively by the military. Although not widely fielded until World War I, early machine guns were being used by the military in the late 19th century (e.g., the Gatling gun). They are primarily defensive weapons, mainly because of the difficulties involved in moving and placing them, and their inherent lack of accuracy. In contrast, light machine guns (such as the U.S. military's M249 Squad Automatic Weapon and the M60, both of which are small-caliber weapons) are often wielded by a single infantryman; they provide a high rate of fire typically used as either suppressing fire or covering fire during infantry movement. Machine guns are also often mounted on vehicles or helicopters, and have often been used since World War II as offensive weapons in fighter aircraft and tanks (e.g., for air combat or suppressing fire for ground troop support). A submachine gun is a machine gun that fires cartridges that would otherwise be used in a handgun. Probably the most well-known example of a submachine gun is the Thompson gun (the "Tommy Gun" of gangster movies), which fires .45 ACP cartridges. In United States law, a Machine Gun is defined (in part) by The National Firearms Act of 1934, United States code Title 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as: "... any weapon which shoots ... automatically more than one shot, without manual reloading, by a single function of the trigger." In the United States, purchases of machine guns manufactured after 1986 by civilians were banned by the Firearm Owners Protection Act (FOPA), passed in that year. Importation of machine guns for civilian sale in the U.S. was banned by the Gun Control Act of 1968. Machine guns manufactured prior to 1986 or imported prior to 1968 can still be legally transferred to civilians who pay a substantial tax to the BATFE and pass a background investigation. In addition, "transferable" machine guns must have been registered with the BATFE prior to 1986. Machine Gun parts kits (which do not include a functional receiver) can be transferred without restriction. Permission must be received from BATFE to move a machine gun between states. One of the most popular, most produced and most used machine guns in the world is the Soviet AK-47. It served in the Soviet army as standard infantry weapon issue, as well as in many other east-block states. It is still used as standard military equipment in some former Warsaw Pact countries, as well as being used by many criminal or terrorist organisations worldwide.

Loading and firing mechanisms

Cannon

The cannon is loaded with gunpowder and the cannonball through the muzzle, while a fuse is placed at the rear. This fuse is lighted, causing the gunpowder to ignite and propel the cannonball. Most cannons were land- or ship-based guns, although hand cannons also existed. In military use, the standard cannon was tremendously powerful, while hand cannon was somewhat useless. In the 19th century, the muzzle-loaded cannon was made obsolete by the breech-loaded artillery piece with a rifled barrel.

Muzzleloader

Muzzle-loading muskets (smooth-bored long guns) were among the first small arms developed. The firearm was loaded through the muzzle with gunpowder, optionally some wadding and then a bullet (usually a solid lead ball, but musketeers could shoot stones when they ran out of bullets). Greatly improved muzzleloaders (usually rifled instead of smooth-bored) are manufactured today and have many enthusiasts, many of whom hunt large and small game with their guns. Muzzleloaders have to be manually reloaded after each shot; a skilled archer could fire multiple arrows faster than most early muskets could be reloaded and fired, although by the mid-18th century, when muzzleloaders became the standard small armament of the military, a well-drilled soldier could fire six rounds in a minute using prepared cartridges in his musket. Before then, effectiveness of muzzleloaders was hindered by both the low reloading speed and, before the firing mechanism was perfected, the very high risk posed by the weapon to the person attempting to fire it. One interesting solution to the reloading problem was the "Roman Candle Gun". This was a muzzleloader in which multiple charges and balls were loaded one on top of the other, with a small hole in each ball to allow the subsequent charge to be ignited after the one ahead of it was ignited. It was neither a very reliable nor popular firearm, but it enabled a form of "automatic" fire long before the advent of the machine gun. http://www.scotwars.com/html/equip_firearms2.htm#3

Matchlock

Matchlocks were the first and simplest small arms firing mechanisms developed. Using the matchlock mechanism, the powder in the gun barrel was ignited by a piece of burning cord called a "match". The match was wedged into one end of an S-shaped piece of steel. As the trigger (often actually a lever) was pulled, the match was brought into the open end of a "touch hole" at the base of the gun barrel, which contained a very small quantity of gunpowder, igniting the main charge of gunpowder in the gun barrel. The match usually had to be relit after each firing.

Wheellock

The wheellock action, a successor to the matchlock, predated the flintlock. Despite its many faults, the wheellock was a significant improvement over the matchlock in terms of both convenience and safety, since it eliminated the need to keep a smoldering match in close proximity to loose gunpowder. It operated using a small wheel much like that on cigarette lighters which was wound up with a key before use and which, when the trigger was pulled, spun against a flint, creating the shower of sparks that ignited the powder in the touch hole. Supposedly invented by Leonardo da Vinci, the Italian Renaissance man, the wheel lock action was an innovation that was not widely adopted.

Flintlock

The flintlock action was a major innovation in small arms design. The spark used to ignite the gunpowder in the touch hole was supplied by a sharpened piece of flint clamped in the jaws of a "cock" which, when released by the trigger, struck a piece of steel called the "frizzen" to create the necessary sparks. (The spring loaded arm that holds a piece of flint or pyrite is refered to as a cock because of its resemblance to a rooster.) The cock had to be manually reset after each firing, and the flint had to be replaced periodically due to wear from striking the frizzen. (See also flintlock mechanism, snaphance, miquelet) The flintlock was widely used during the 18th and 19th centuries in both muskets and rifles.

Percussion cap

Percussion caps (caplock mechanisms), coming into wide service in the 19th century, were a dramatic improvement over flintlocks. With the percussion cap mechanism, the small primer charge of gunpowder used in all preceding small arms was replaced by a completely self-contained explosive charge contained in a small brass "cap". The cap was fastened to the touch hole of the gun (extended to form a "nipple") and ignited by the impact of the gun's "hammer". (The hammer is roughly the same as the cock found on flintlocks except that it doesn't clamp onto anything.) In the case of percussion caps the hammer was hollow on the end to fit around the cap in order to keep the cap from fragmenting and injuring the shooter. Once struck, the flame from the cap in turn ignited the main charge of gunpowder, as with the flintlock, but there was no longer any need to charge the touch hole with gunpowder, and even better, the touch hole was no longer exposed to the elements. As a result, the percussion cap mechanism was considerably safer, far more weatherproof, and vastly more reliable (cloth-bound cartridges containing a premeasured charge of gunpowder and a ball had been in regular military service for many years, but the exposed gunpowder in the entry to the touch hole had long been a source of misfires). All muzzleloaders manufactured since the second half of the 19th century use percussion caps except those built as replicas of the flintlock or earlier small arms.

Cartridges

A major innovation in small arms (and light artillery) came in the second half of the 19th century when ammunition, previously delivered as separate bullets and powder, was combined in a single metallic (almost always brass) cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. Before this, a "cartridge" was simply a premeasured quantity of gunpowder together with a ball in a small cloth bag, which also acted as wadding for the charge and ball. This early form of cartridge had to be rammed into the muzzleloader's barrel, and either a small charge of gunpowder in the touch hole or an external percussion cap mounted on the touch hole ignited the gunpowder in the cartridge. Cartridges with built-in percussion caps (called "primers") continue to this day to be the standard in firearms. In cartridge-firing firearms, a hammer (or a firing pin struck by the hammer) strikes the cartridge primer, which then ignites the gunpowder within. The primer charge is at the base of the cartridge, either within the rim (a "rimfire" cartridge) or in a small percussion cap embedded in the center of the base (a "centerfire" cartridge). As a rule, centerfire cartridges are more powerful than rimfire cartridges, containing more gunpowder and (usually) larger diameter bullets. Caseless cartridges are now being explored: instead of using brass as the cartridge case, these would hold the cartridge together with paper or some other substance that is destroyed when the gun is fired, eliminating the problem of brass casings ejecting and littering the ground. Caseless cartridges and the guns that would use them are still prototypes, although the idea of caseless cartridges can be traced to the musket "cartridges" widely used by the 18th-century military. Nearly all contemporary firearms load cartridges directly into their breech. Some additionally or exclusively load from a magazine that holds multiple cartridges. A magazine is a box or cylinder that is designed to be reusable and is detachable from the gun. Some magazines, such as those of the Garand are loaded by using a clip, which is a device that looks like a rail holding the ammunition by the case base. In most cases, a magazine and a clip are different in that the former's function is to feed ammunition into the firearm's breech, while the latter's is only to "charge" a magazine with fresh ammunition.

Repeating, semiautomatic, and automatic weapons

Many small arms are "single shot" firearms: i.e., each time a cartridge is fired, the operator must manually recock the firearm and load another cartridge. A firearm that can load multiple cartridges as the weapon is recocked is considered a repeating weapon or simply a "repeater". A firearm that automatically recocks and reloads the next round with each trigger pull is considered a semiautomatic weapon. An automatic (or "fully automatic") weapon is one that automatically recocks, reloads, and refires as long as the trigger is depressed. Many modern military firearms have a "selective-fire" option, which is a mechanical switch that allows the weapon be fired either in the semiautomatic or fully automatic mode. In the current M16A2 and M16A4 variants of the U.S.-made M16, continuous full-automatic fire is not possible, having been replaced by an automatic burst of three cartridges that makes full-automatic fire considerably more accurate. It is sometimes debated which is the "best" military small arm, the former Soviet Union's 7.62x39mm- Kalashnikov AK-47 or the U.S.-manufactured .223-caliber M16: the highly reliable and inexpensive but heavy and bulky AK-47 has been widely adopted by many small countries, including many current and former Communist nations. The much lighter and far more accurate M16 (and its .223 cartridge in particular) has found wide adoption among NATO members and military allies of the United States (see also AK-47 vs. M16). The first "rapid firing" weapons were usually similar to the 19th-century Gatling gun, which would fire cartridges from a magazine as fast as and as long as the operator turned a crank. Eventually, the "rapid" firing mechanism was perfected and miniaturized to the extent that either the recoil of the firearm or the gas pressure from firing could be used to operate it (which made the firing mechanisms truly "automatic"). Automatic rifles such as the Browning Automatic Rifle (the "BAR") were in common use by the military during the early part of the 20th century, and automatic rifles that fired handgun rounds, known as submachine guns, also appeared in this time. Submachine guns (such as the well-known Thompson gun) were originally about the size of carbines. In the latter half of the 20th century, submachine guns were being miniaturized to the point of being only slightly larger than some large handguns. The most widely used submachine gun at the end of the 20th century was the Heckler & Koch MP5. The MP5 is actually designated as a "machine pistol" by Heckler & Koch (MP5 stands for Machine Pistol 5), although some reserve this designation for even smaller submachine guns such as the MAC-10, which are about the size and shape of pistols. Nazi Germany brought the world's attention to what eventually became the class of weapon most widely adopted by the military: the so-called assault rifle. An assault rifle is usually slightly smaller than a military rifle such as the M1 Garand but has selective fire (civilian assault rifle look-alikes are strictly semiautomatic). Soviet engineer Mikhail Kalashnikov quickly adapted the concept to the AK-47, which has become the world's most widely used assault rifle. In United States, John Garand, the inventor of the M1 Garand rifle used by the U.S. military during World War II, adapted the assault rifle design to produce the M14, which was used by the U.S. military until the 1960s. The significant recoil (hence inaccuracy) of the M14 when fired in full automatic mode was seen as a problem, however, and in the 1960s it was replaced by Eugene Stoner's AR-15, which also marked a switch from the high-powered but heavy .30-caliber rifle used by the U.S. military since World War I to the much smaller but far lighter and light recoiling (more accurate) .223-caliber rifle. The military later redesignated the AR-15 as the "M16". The civilian version of the M16 continues to be known as the AR-15 and looks exactly like the military version, although it is strictly a semiautomatic firearm.

External resources

- [http://dmoz.org/Shopping/Recreation/Guns DMOZ Open Directory Project - Guns]
- [http://dmoz.org/Shopping/Recreation/Guns/Antiques_and_Collectibles DMOZ Open Directory Project - Guns, Antique] Category:Ammunition Category:Firearms ja:銃

External links

- [http://www.nazarian.no/def.asp?lang=0&page_id=1 Nazarian`s Gun`s Recognition Guide]
- [http://world.guns.ru/main-e.htm Online encyclopedia of firearms and ammunition of the XX and XXI centuries.]
- [http://www.self-defender.net/weapons/rifles.htm Modern Civilian And Military Rifles]

Bullet

A bullet is a projectile shot by a gun, usually made of a metal alloy. In contrast to a shell, a bullet does not contain explosives. The term bullet refers specifically to the metal slug that is propelled from a firearm. Although the term is occasionally used to refer to the combination of bullet, case, gunpowder, and primer, such an item is properly called a cartridge. A cartridge without a bullet is called a blank.

Material

Bullets are classically molded from a mixture of lead and tin. Typesetter's lead (used to mold Linotype), works very well. Lead is a popular choice because it is highly dense (providing a high amount of mass — and thus, kinetic energy — for a given volume) and is cheap to obtain and fabricate. However, a projectile in flight undergoes significant external forces which may dissipate its ability to provide maximum energy to the target. At speeds of greater than 300 m/s (1000 ft/s) (common in most handguns), lead begins to deform during flight due to its softness and low tensile strength. At speeds greater than 600 m/s (2000 ft/s) (such as high-powered rifles, which may have muzzle velocities exceeding 1000 m/s (3500 ft/s)), unjacketed lead bullets may experience structural failure and disintegrate in flight due to very high centrifugal force imparted by the spin used to stabilize its flight. Also, as velocities are increased, the bullet will begin to leave very thick and heavy residues of lead in the barrel that damages the bullet and destroys accuracy on subsequent shots. Alloying the lead with a small percentage of tin and/or antimony helps this situation somewhat, but is not completely effective as velocities are increased. Bullets intended for high-velocity applications generally have a lead core jacketed with copper or steel; the thin layer of copper protects the lead core during flight, delivering it intact to the target. There, the heavy lead core delivers its kinetic energy to the target. Some premium bullets may be made entirely of copper or brass. Steel jacketed bullets are actually copper-dipped so that the steel will not damage the rifling in the gun barrel. Armor Piercing bullets are jacketed designs where the core material is a very hard and high-density metal such as tungsten, tungsten carbide, depleted uranium, or steel. Frangible bullets are the opposite of Armor Piercing designs, and are intended to disintegrate into tiny particles upon impact to minimize their penetration. An example is the Glaser Safety Slug. Bismuth and Tungsten bullet alloys are available, and prevent release of toxic lead into the environment. Neither tin nor copper are toxic to mammals. Rubber bullets, plastic bullets, and beanbags are designed to be non-lethal, for example for use in riot control. Wax bullets are often used by quick draw shooters for their own safety.

Design

Wax bullets;
2. the casing, which holds all parts together;
3. the explosive, for example gunpowder or cordite, which serves as a propellant;
4. the rim, at the base of the cartridge;
5. the primer, which ignites the gunpowder.]] Bullet designs have to solve several problems:
- The bullet must form a seal with the gun's bore. The worse the seal, the more gas generated by the explosion leaks past the bullet reducing the efficiency. There are two types of seals (gas checks) in common use. One is a slight indentation in the back of the bullet. Gas pressure forces the metal lip against the bore. Another type is a basic labyrinthine seal: one or two bands of raised material go around the bullet.
- The bullet must engage the rifling without damaging the gun's bore. Usually there is a raised band or two of material around its middle. This will be something soft, such as copper, tin, plastic or lead, which will prevent wear of the harder steel gun barrel. AP (Armour Piercing) rounds made of bronze, hardened steel or tungsten (and even depleted uranium) cause barrel wear, and so are normally covered. Where these bands are a different material, they are called "driving bands" as they drive the bullet around the rifling. Bullets must have a surface which works well with the surface; it must seal, but not have too much friction. What happens to a bullet inside of a gun, is part of the internal ballistics. In smooth-bore firearms there the bullet must minimize the gas the goes around it, but not so tight it cannot leave the barrel. In rifled barrels, the bullet must do the latter, but also engage the rifling so spin is imparted to the bullet. The spin stabilizes the bullet in flight (see physics). It is important that the bullet have its center of mass at its center, otherwise the spin will cause it to wobble. Materials which have a low friction (compared to other metals) in relation to steel are used to sheath modern bullets and engage the rifling; they must be soft enough to minimize wear on the rifling. Once it leaves the barrel, it is governed by external ballistics. Here, the bullet's shape is very important for aerodynamics, as is the physics of spinning things (for bullets that are spun). In the past, with smooth-bore firearms, a sphere shape was common because no matter how it turned, it presented a uniform front. This shape was also used for early rifled firearms as well. It offers the lowest overall surface area for a given volume as well. Rifling stabilizes the bullet in flight, which allowed for new shapes with advantages over spheres. This allowed for more cylinder shaped rounds, and ones shaped for lower drag. With less drag, the bullet can go farther. A parabolic or pointed head can result in less drag, as can features like a boat tail. However, this must be balanced against increasing the surface area of the bullet too much. If the bullets cross-section is decreased, it must then be longer for a given volume and weight of material. Also, as a practical matter there is no perfect shape since the bullet must travel at different speeds and must travel in different atmospheric conditions. This aspect must be balanced against other aspects, especially what happens when the bullet hits something and what happens inside the firearm. See Terminal ballistics and/or Stopping power for an overview of how bullet design effect what happens when a bullet hits something, and how this impacts its design. What happens to the bullet is dictated as much by what it hits and how it hits, as by the bullet itself (just like how its interaction with air was critical in external ballistics). Bullets are generally designed to penetrate, deform, and/or break apart. For a given material and bullet, which of these happens is determined especially by the strike velocity.

Types

There are many types of bullets for different applications. For example, here are some of the rounds used in one machine gun series:
- M61 Armour-piercing, has higher penetration of hard materials like steel.
- M62 Tracer, has incendiary material in the back of the bullet so that its path in the air is easily visible.
- M80 Ball, a brass-enclosed lead bullet
- M82 Blank, has powder but no bullet (used for firing salutes etc.)
- M63 Dummy, has a bullet but no powder (used for loading and unloading exercises, etc.) Tracer bullets have a hollow back, filled with a flare material. Usually this is a mixture of magnesium, perchlorate, and chromium, to yield a bright red color. A new design is trying to use a Light Emitting Diode (LED) instead, but the cost and complexity would seem to negate any advantage. Tracer material burns out after a certain amount of time. Tracers are usually mixed in with other kinds of rounds, such as every 7th round for example. Lead is the typical material used; it is relatively cheap, expands well, and can be hardened by alloying with tin and antimony. Actual bullet shapes are many and varied, and an array of them can be found in any reloading manual that sells bullet moulds. [http://www.rcbs.com/default.asp?menu=1&s1=4&s2=9&s3=83 RCBS] are one of many makers, and the link will let you see many different designs, starting with the basic round ball. With a mould, bullets can be made at home for reloading your own ammunition, where local laws allow. Cast and jacketed bullets are also commercially available from numerous manufacturers for handloading and are much more convenient than casting bullets from bulk lead.

Manufacture

Lead bullets

Small-scale manufacture is accomplished with individual molds, and hand-file to remove the mold artifacts. Larger scales use multiple molds, and abrasive tumbling to remove separation lines and other mold artifacts. Most lead bullets manufacturers today use a wire and stamp method under extremely high pressure that may reach as high as 80,000 pounds per square inch (550 MPa). The bullets are then swaged through a sizing die to their final dimension.

Jacketed bullets

Lead ingots are extruded into wire under high pressure. Then the wire is stamped into bullet cores and swaged to size. The bullet jacket is punched out of copper plate of appropriate thickness. These copper "plugs" are then extruded into a cup shape by the use of dies. Picture pushing your finger through a piece of gum. The lead core is inserted and the jacketed core is worked through a series of dies until it closes around the core.

Treaties

The Geneva Accords on Humane Weaponry and the Hague Convention prohibit certain kinds of ammunition for use by armies. These include exploding, poisoned and expanding bullets.

History

The first bullets

Almost undoubtedly the first "bullets" were much like crossbow quarrels, fired from metal and wooden guns immediately after the introduction of gunpowder in Europe. Large guns and cannon fired stone balls until the mid-15th century when metal balls began to be cast. The development of the hand culverin and matchlock arquebus brought about the use of cast lead balls as projectiles. "Bullet" is derived from the French word "boulette" which roughly means "little ball." The original musket bullet was a spherical leaden ball two sizes smaller than the bore, wrapped in a loosely fitting paper patch which formed a tight seal so the full pressure of the expanding gas would propel the bullet. The loading was, therefore, easy with the old smooth-bore Brown Bess and similar military muskets. The original muzzle-loading rifle, on the other hand, with a closely fitting ball to take the rifling grooves, was loaded with difficulty, particularly when foul, and for this reason was not generally used for military purposes.

The bullet takes shape

As firearms became more technologically advanced from 1500 to 1800, the bullets changed little. They remained simple round lead balls, differing only in their size. Even with the advent of rifling the bullet itself didn't change, but was wrapped in a leather patch to grip the rifling grooves. Nevertheless, many ideas were not pursued, and the history books are full of brilliant ideas that failed to catch on. The first half of the 19th century saw a distinct change in the shape and function of the bullet. In 1826 Delirque, a French infantry officer, invented a breech with abrupt shoulders on which a spherical bullet was rammed down until it caught the rifling grooves. Delirque's method, however, deformed the bullet and was inaccurate. Among the first "bullet-shaped" bullets was designed by Captain John Norton of the British Army in 1823. Norton's bullet had a hollow base which expanded under pressure to catch the rifling grooves once fired but the British Board of Ordnance rejected it because spherical bullets has been in use for the last 300 years. Renowned English gunsmith William Greener invented the Greener bullet in 1836. It was very similar to Norton's bullet except that the hollow base of the bullet was fitted with a wooden plug which more reliably forced the base of the bullet to expand and catch the rifling. Tests proved that Greener's bullet was extremely effective but it was rejected because, being two parts, it was judged too complicated to produce. The soft lead bullet that came to be known as the minié ball, (or minnie ball) was first introduced in 1847 by Claude Étienne Minié (1814? - 1879), a captain in the French Army. It was nearly identical to the Greener bullet: as designed by Minié the bullet was conical in shape with a hollow cavity in the rear end, which was fitted with a little iron cap instead of a wooden plug. When fired, the cap would force itself into the hollow cavity, forcing the sides of the bullet to expand and engage the rifling. In 1855 the British adopted the minie ball for their Enfield rifles. It was in the American Civil War, however, that the minie ball saw the most use. Roughly 90% of the battlefield casualties in the war were caused by minie balls fired from rifles. 1855 Between 1854 and 1857 Sir Joseph Whitworth conducted a long series of rifle experiments, and proved, among other points, the advantages of a smaller bore and, in particular, of an elongated bullet. The Whitworth bullet was made to fit the grooves of the rifle mechanically. The Whitworth rifle was never adopted by the government, although it was used extensively for match purposes and target practice between 1857 and 1866, when it was gradually superseded by Metford's. About 1862 and later, W. E. Metford had carried out an exhaustive series of experiments on bullets and rifling, and had invented the important system of light rifling with increasing spiral, and a hardened bullet. The combined result of the above inventions was that in December 1888 the Lee Metford small-bore (0.303") rifle, Mark I, (photo of cartridge on right) was finally adopted for the British army. The Lee-Metford was the predecessor of the Lee-Enfield.

The modern bullet

The next important change in the history of the rifle bullet occurred in 1883, when Major Rubin, director of the Swiss Laboratory at Thun, invented the small-calibre rifle, one of whose essential features was the employment of an elongated compound bullet, with a lead core in a copper envelope. The copper jacketed bullet allows much higher muzzle velocities than lead alone, as copper has a much higher melting point, greater specific heat capacity, and is harder. Lead bullets fired at high velocity may suffer surface melting due to hot gases behind and friction with the bore. This can allow the gas past the bullet, deforming it and destroying accuracy. Very rapid acceleration of a lead bullet may cause the rifling to strip, reducing the spin imparted to the bullet, and also destroying accuracy. A gas check may be used for some lead bullets, but are only useful up to a certain muzzle velocity, as they only protect the base of the bullet from melting, not the sides. It normally takes the form of a very thin copper disc attached to the rear of the bullet. The modern bullet has had minor refinements, but the basic bullet and self-contained cartridge has since remained almost unchanged for over 130 years. In the late 1950s, engineers noted that a reverse ogive on the rear, a boat-tail increased range on supersonic bullets. At one point in the 1960s, it looked as though flechettes might replace bullets, but bullets proved more economical, and no less destructive. Other bullet types: soft point bullet, full metal jacket bullet, armor piercing bullet, Teflon coated bullet, Glaser Safety Slug

Bullet acronyms

- BBWC — Bevel Base Wadcutter
- BT — Boat Tail
- BTHP — Boat Tail Hollow Point
- FMJ — Full Metal Jacket
- FP — Flat Point
- GD — Gold Dot HP
- GS — Golden Saber HP
- HP — Hollow Point
- HBWC — Hollow Base Wadcutter
- HS — Hydra Shok HP
- J — Jacketed
- JFP — Jacketed Flat Point
- JHC — Jacketed Hollow Cavity
- JHP — Jacketed Hollow Point
- L — Lead
- LFN — Long Flat Nose
- LFP — Lead Flat Point
- LRN — Lead Round Nose
- LSWC — Lead Semi-Wadcutter
- LSWC-GC — Lead Semi-Wadcutter Gas Checked
- LWC — Lead WadCutter
- LTC — Lead Truncated Cone
- RN — Round Nose
- RNFP — Round Nose Flat Point
- SJ — Semi Jacketed
- SJHP — Semi Jacketed Hollow Point
- SP — Soft Point
- ST — Silver Tip HP
- SWC — Semi Wadcutter
- TC — Truncated Cone
- TMJ — Total Metal Jacket
- WC — WadCutter
- WLN — Wide Long Nose
- XTP — Extreme Terminal Performance

American football

American football rules shape, and usually has a large set of stitches along one side.]] American football, known in North America simply as football, is a competitive team sport. The object of the game is to advance the football towards the opposing team's end zone and score points. The ball can be advanced by carrying the ball, or by throwing or handing it from one teammate to the other. Points can be scored in a variety of ways, including carrying the ball over the goal line, throwing the ball to another player past the goal line or kicking it through the goal posts. The winner is the team with the most points when the time expires. Outside of the United States, Canada, and a few other countries such as American Samoa, the sport is usually referred to as American football (or sometimes as gridiron) to differentiate it from other football games, especially association football and rugby football. American football evolved as a separate sport from rugby football in the late 19th century. Arena football is a variant of American football.

Popularity

Since the 1960s, football has surpassed baseball as the most popular spectator sport in the United States. The 32-team National Football League (NFL) is the most popular and only major professional American football league. Its championship game, the Super Bowl, is watched by nearly half of US television households, and is also televised in over 150 other countries. Super Bowl Sunday has become an annual ritual in late January or early February. It is also the most watched sport on television in the US. The NFL also operates a developmental league, NFL Europe, with 6 teams based in European cities. NFL Europe player tries to thwart his progress.]] College football is also extremely popular throughout the U.S., especially in markets not served by an NFL team. Several college football stadiums seat more than 100,000 fans -- which regularly sell out. Even high school football games can attract five-figure crowds, especially in hotbeds like Western Pennsylvania, Ohio, Florida, Texas and Georgia. The weekly autumn ritual of college and high-school football -- which includes marching bands, cheerleaders and parties -- is an important part of the culture in much of smalltown America. Football is also played recreationally by amateur club and youth teams (e.g., the Pop Warner little-league programs). There are also many "semi-pro" teams in leagues where the players are paid to play, but at a small enough salary that they generally must also hold a full-time job. Organized football is played almost exclusively by men and boys.

The rules of American football

Objective: Like most other games of football, the object of American football is to advance the ball towards the opponent's end of the field and score more points than the opposing team within a set time limit.

Field and players

football The American football field is often called the gridiron because the markings on the field resemble that type of grill that can be used to cook food over a fire. The game is played on a rectangular field 120 yards (110 metres) long by 53 1/3 yards (49 metres) wide. The longer boundary lines are sidelines, while the shorter boundary lines are end lines. Near each end of the field is a goal line; they are 100 yards apart. A scoring area called an end zone extends 10 yards beyond each goal line to each end line. Yard lines cross the field every 5 yards, and are numbered from each goal line to the 50-yard line, or midfield (similar to a typical rugby league field). Two rows of lines, known as hash marks parallel the side lines near the middle of the field. All plays start with the ball on or between the hash marks. At the back of each end zone are two goal posts (also called uprights) that are 18.5 feet apart. The posts are connected by a crossbar 10 feet from the ground. Successful kicks must go above the crossbar and between the uprights. (At many fields the uprights and crossbar are attached by a curved bar to a post outside the field of play, to reduce the chance of players running into the supports.) Each team has 11 players on the field at a time. However, teams may substitute for any or all of their players between plays. As a result, players have very specialized roles, and almost all of the 53 players on an NFL team will play in any given game. Thus, teams are divided into three separate units: the offense, the defense and the special teams (see below).

Game duration

A standard football game consists of four 15-minute (typically 12 minutes in high school football) periods (called quarters), with an intermission (called halftime) after the second quarter. The clock stops after certain plays; therefore, a game can last considerably longer (often more than three hours in real time). If an NFL game is tied after four quarters, the teams play up to another 15 minutes. The first team that scores wins; if neither team scores, the game is a tie. College overtime rules are more complicated and are described at Overtime (sport).

Advancing the ball

Advancing the ball in American football resembles the six-tackle rule and the play-the-ball in rugby league football. The team that takes possession of the ball (the offense) has four attempts, called downs, to advance the ball 10 yards towards their opponent's (the defense's) end zone. When the offense gains 10 yards, it gets a first down, or another set of four downs to gain 10 yards. If the offense fails to gain a first down, it loses possession of the ball. Except at the beginning of halves and after scores (see Kickoffs and free kicks below), the ball is always put into play by a snap. All players line up facing each other at the line of scrimmage (the position on the field where the play begins). One offensive player, the center, then passes (or "snaps") the ball between his legs to a teammate, usually the quarterback. Players can then advance the ball in two ways:
- By running with the ball, also known as rushing.
- By throwing the ball to a teammate, known as passing. The forward pass is a key factor distinguishing American and Canadian football from other football sports. The offense can throw the ball forward only once on a play and only from behind the line of scrimmage. The ball can be thrown sideways or backwards at any time. This type of pass is known as a lateral and is much rarer in American football than in rugby league or rugby union. A play or down ends, and the ball becomes dead, after any of the following:
- The player with the ball is tackled to the ground by a member of the opposing team, or has his forward progress stopped (as determined by an official).
- A forward pass flies out of bounds or touches the ground before it is caught. This is known as an incomplete pass. The ball is returned to the original line of scrimmage for the next down.
- The ball or the player with the ball goes beyond the dimensions of the field (out of bounds).
- A team scores. Often an official will blow a whistle to notify all players that the play is over. The ball may also change position as a result of penalties. These penalties may be incurred by either the offensive or defensive team. Generally, penalties involve a loss of yardage for the penalized team, and sometimes an automatic first down. Field officials signal that a penalty has been incurred by throwing a yellow flag onto the field near the site of the penalty, while the play continues. When the play ends, the referee names the penalty and the consequences thereof.

Changes of possession

The offense maintains possession of the ball unless one of the following things happens:
- The team fails to get a first down, that is, move the ball forward at least 10 yards in four downs. The defensive team takes over the ball at the spot where the play ends.
- The offense scores a touchdown or field goal. The team that scored then kicks off the ball to the other team. (See Scoring and Kickoffs below.)
- The offense punts the ball to the defense. A punt is a kick in which a player drops the ball and kicks it before it hits the ground. Punts are nearly always made on fourth down, when the offensive team does not want to risk giving up the ball to the other team at its current spot on the field (through a failed attempt to make a first down) and feels it is too far from the other team's goal posts to kick a field goal.
- A defensive player catches a forward pass. This is called an interception, and the player who makes the interception can run with the ball until tackled, forced out of bounds, or scores.
- An offensive player drops the ball (a fumble), and a defensive player picks it up. As with interceptions, a player recovering a fumble can run with the ball until tackled or forced out of bounds. Lost fumbles and interceptions are together known as turnovers.
- The offensive team misses a field goal attempt. The defensive team gets the ball at the spot where the previous play began (or, in the NFL, at the spot of the kick). If the unsuccessful kick was attempted from very close to the end zone, the other team gets the ball at its own 20-yard line (that is, 20 yards from the end zone).
- An offensive player is tackled or forced out of bounds in his own end zone. This rare occurrence is called a safety. (See Scoring below.)

Scoring

A team scores points by the following plays:
- A touchdown (TD) is worth 6 points. A touchdown is scored when a player runs the ball into or catches a pass in his opponent's end zone.
- After a touchdown, the scoring team attempts a conversion. The ball is placed at the other team's 3-yard-line (the 2-yard-line in the NFL). The team can attempt to kick it over the crossbar and through the goal posts for 1 point (an extra point), or run or pass it into the end zone for 2 points (a two-point conversion). The extra point is usually attempted because it is significantly easier to achieve.
- A field goal (FG) is worth 3 points, and it is scored by kicking the ball over the crossbar and through the goal posts. Field goals must be placekicked, that is, kicked when the ball is held vertically against the ground by a teammate. A field goal is usually attempted on fourth down instead of a punt when the ball is close to the goal line.
- A safety is worth 2 points. A safety is scored by the defense when the offensive player in possession of the ball is forced back into his own end zone and is tackled there, or fumbles the ball out of the end zone. Certain penalties by the offense occurring in the end zone also result in a safety.

Kickoffs and free kicks

Each half begins with a kickoff. Teams also kick off after scoring touchdowns and field goals. The ball is kicked from a kicking tee, which is made from one's own 30-yard line in the NFL and from the 35-yard line in college football. The other team's kick returner tries to catch the ball and advance it as far as possible. Where he is stopped is the point where the offense will begin its drive, or series of offensive plays. If the kick returner catches the ball in his own end zone, he can either run with the ball, or elect for a touchback by kneeling in the end zone. The receiving team can then start its offensive drive from its own 20-yard line. A touchback can also occur when the kick goes out of the end zone. Punts and turnovers in the end zone can also end in touchbacks. If a kickoff goes out of bounds over the sidelines without being interfered by the recieving team, the ball will be placed 30 yards from the spot of the kickoff (traditionally at the receiving team's 40-yard line in the NFL or the 35-yard line in college football). After safeties, there is a free kick instead of a kickoff. A free kick is made from a team's own 20-yard-line and can be punted or placekicked.

The players

As noted above, most football players have highly specialized roles. At the college and NFL levels, most play only offense or only defense.

Offense

- The offensive line (OL) consists of five players (two offensive tackles (OT), two guards (G), and a center (C)) whose job is to protect the passer and clear the way for runners by blocking members of the defense. All plays begin with the center handing the ball backwards between his legs, or snapping it, to a teammate, usually the quarterback.
- The quarterback (QB) receives the ball on most plays. He then hands or tosses it to a running back, throws it to a receiver or runs with it himself.
- Running backs (RB) line up behind or beside the QB and specialize in rushing with the ball. They also block, catch passes and, on rare occasions, pass the ball to others. There are two main kinds of running backs: fullbacks (FB), who usually block, and halfbacks or tailbacks, who are more likely to carry the ball.
- Wide receivers (WR) line up near the sidelines. They specialize in catching passes.
- Tight ends (TE) line up outside the offensive line. They can either play like wide receivers (try to catch passes) or like offensive linemen (protect the QB or create spaces for runners). Not all of these types of players will be in on every offensive play. Teams can vary the number of wide receivers, tight ends and running backs on the field at one time.

Defense

- The defensive line (DL) consists of three to five players (two defensive ends, one or two defensive tackles (DT), and possibly one nose guard (DT)) who line up across from the offensive line. They try to tackle the running backs before they can gain yardage or the quarterback before he can throw a pass.
- At least four players line up as defensive backs (DB). They may be cornerbacks (CB), free safeties (FS), or strong safeties (SS). They cover the receivers and try to stop pass completions. They occasionally rush the quarterback. However, in high school, it is not uncommon to see a team go without the addition of a strong safety, due to the inexperience of high school quarterbacks and wide receivers.
- The other players on the defense are known as linebackers (LB). They line up between the defensive line and backs and may either rush the quarterback or cover receivers and/or running backs. However, they are more proficient at stopping rushing plays. They are split up into two different types, middle linebackers and outside linebackers. A middle linebacker/s is committed to runs up the middle (dives, powers). The outside linebackers are committed to runs to the outside (sweeps) or misdirection runs (counters).

Special teams

The units of players who handle kicking plays are known as special teams. Special-teams players include the punter (P), who handles punts, and the placekicker or kicker (PK or K), who kicks off and attempts field goals and extra points. Field goal and extra point attempts also require a holder who receives the ball from the center and holds it in a position that allows the kicker to easily kick the ball. The holder is usually a backup quarterback, as the field goal formation is very occasionally used for a pass or run play instead in a last-ditch effort to get a first down or touchdown, called a fake field goal. Kickers have also (very rarely) been known to take the snap and run a fake field goal play themselves.

Basic football strategy

To many fans, the chief draw of football is the chess game that goes on between the two coaching staffs. Each team has a playbook of dozens to hundreds of plays. Plays are the directions for what the players should do on a down. Some plays are very safe; they are very likely to get a few yards, but not much more than that. Other plays have the potential for long gains but a greater risk of a loss of yardage or a turnover. Generally speaking, rushing plays are less risky than passing plays. However, there are relatively safe passing plays and risky running plays. To fool the other team, there are passing plays designed to look like running plays and vice versa. There are many trick or gadget plays, such as when a team lines up like it is going to kick and then tries to run or pass for a first down. Such high-risk plays are a great thrill to the fans when they work. However, they can spell disaster if the opposing team realizes the deception and acts accordingly. It has been said that football is the closest sport that strategically resembles real war, which may explain why it is by far the most popular sport in the American military. In fact, the United States Military Academy, the United States Naval Academy, and the United States Air Force Academy each field football teams that participate in the collegiate leagues. The Army and Navy have a particularly historic rivalry.

Development of the game

Both American football and soccer have their origins in varieties of football played in the United Kingdom in the mid-19th century, and American football is directly descended from rugby football. Rugby was first introduced to North America in Canada, brought by the British Army garrison in Montreal which played a series of games with McGill University. Both Canadian and American football evolved from this point. For an in-depth overview of the differences and similarities of Canadian football and American football see: Comparison of Canadian and American football American colleges spearheaded the growth of football. The [http://www.scarletknights.com/football/history/first_game.htm first inter-collegiate football game] was played between Rutgers and Princeton Universities on November 6, 1869. The game was won by Rutgers (6-4) although "The game, which bore little resemblance to its modern-day counterpart, was played with two teams of 25 men each under rugby-like rules, but like modern football, it was “replete with surprise, strategy, prodigies of determination, and physical prowess,” to use the words of one of the Rutgers players." - [http://www.scarletknights.com/football/history/first_game.htm Rutgers Football] American football in its current form grew out of a series of three games between Harvard University and McGill University of Montreal in 1874. McGill played rugby football while Harvard played the Boston Game, which was closer to soccer. As often happened in those days of far from universal rules, the teams alternated rules so that both would have a fair chance. The Harvard players liked having the opportunity to run with the ball, and in 1875 persuaded Yale University to adopt rugby rules for their annual game. In 1876 Yale, Harvard, Princeton, and Columbia formed the Intercollegiate Football Association, which used the rugby code, except for a slight difference in scoring. In 1880 Walter Camp introduced the scrimmage in place of the rugby scrum. In 1882 the system of downs was introduced to thwart Princeton's and Yale's strategy of controlling the ball without trying to score. In 1883 the number of players was reduced, at Camp's urging, to eleven, and Camp introduced the soon standard arrangement of a seven-man offensive line with a quarterback, two halfbacks, and a fullback. On September 3, 1895 the first professional football game was played, in Latrobe, Pennsylvania, between the Latrobe YMCA and the Jeannette Athletic Club. (Latrobe won the contest 12-0.). By the 1890s interlocking offensive formations such as the flying wedge and the practice of teammates physically dragging ball-carrying players forward had made the game extremely dangerous. Despite restrictions on the flying wedge and other precautions, in 1905 eighteen players were killed in games. President Theodore Roosevelt informed the universities that the game must be made safer. To force them to respond to his concerns, he threatened to pressure Congress to make playing football a federal crime. In 1906, two rival organizing bodies, the Intercollegiate Rules Committee and the Intercollegiate Athletic Association, met in New York; eventually they agreed on several new rules intended to make the game safer, among them the addition of a neutral zone between the scrimmage lines and a requirement that at least six players from each team line up on them. The most far-reaching innovation they considered, though, was the legalization of the forward pass. This was very controversial at the time, much derided by purists. As an alternative means of opening out the play, Walter Camp would have preferred widening the field; but representatives from Harvard pointed to recently constructed Harvard Stadium, which could not be widened, and the forward pass was adopted; it has come to shape the whole history of American football, as opposed to its cousins around the world. In 1910, after further deaths, interlocking formations were finally outlawed; and in 1912 the field was changed to its current size, the value of a touchdown increased to 6 points, and a fourth down added to each possession. The game had achieved its modern form.

Problems in Football

Injuries are more common in American football than in many other sports, although rule changes made in the past 90 years (for instance, the elimination of "horse-collar tackles") have gradually lowered the rates of injuries. In addition, protective equipment has become better - for example, the optional leather helmets introduced during the 1890s have been replaced (in several stages) by required high-tech padded plastic helmets with bars protecting the face. More recently, the use of steroids and the extent thereof has become an object of debate in professional, college, and even high school football leagues. (Pop Warner leagues appear to so far be immune to questions of whether players "juice up" or not.) Another problem with football is that it is an expensive sport. The specialized helmets, uniforms, and pads can cost hundreds of dollars. There is a widespread perception that football teams based in schools and public recreational leagues consume far more than their fair share of the sports budget, although sales of tickets to college (and to some extent high school) football games often make it a revenue-producing sport. Pop Warner, home of the Cleveland Browns.]]

Professional, college, and other leagues

Football is played at a number of levels in the United States and abroad. These include the following:
- The National Football League - top-level men's professional league
- College football - played by many US colleges
- The Arena Football League - mid-level men's professional league. Played in indoor stadiums, hence the name "arena" football. One of the nation's fastest-growing sports.
- The Canadian Football League - men's professional league based in Canada, played using a slightly different set of rules known as Canadian football
- The Mexican College Football League or ONEFA - played by many Mexican colleges, with the same rules as in the US
- The North American Football League - Amateur minor league with more than 100 member organizations since 1996,
- Women's American football - since 2000, there has been a surge of women's professional leagues.
- High school football - played by most high schools
- Nine-man football, Eight-man football, and Six-man football - variations of high school football, usually played in sparsely populated areas
- Amateur and youth league football
- Flag football and Touch football - non-tackle; almost exclusively amateur
- Pop Warner or youth football - involves younger children who are too young to play high school, generally in middle school.
- Sprint football - players must weigh no more than 172 pounds
- British Collegiate American Football League (BCAFL) - Fast-growing college football league in the UK The descriptions in this article are based primarily on the current rules of the National Football League (NFL, 1920-present). Differences with college rules will be noted. Professional, college, high school, and amateur rules are similar. Professional leagues that no longer exist include the World Football League (WFL, 1974-75), the United States Football League (USFL, 1983-1985), the XFL (XFL, 2001), the All-America Football Conference (1946-1949) (2 teams are now in the NFL), the World League of American Football (WLAF, 1991-1993 — now NFL Europe), and four separate American Football Leagues (AFL, 1926, 1937-28, 1940-1941 and 1960-1969). The fourth AFL (1960-1969) merged with the NFL in 1970 and now exists (mostly) as the AFC with several new teams. The old NFL appeared as the NFC.

References

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External links

- The [http://www.nfl.com/ National Football League (NFL)] - the top professional league
- [http://www.players.com NFL Players Association]
- NCAA [http://www2.ncaa.org/media_and_events/ncaa_publications/playing_rules/ Playing Rules] (complete college football rules are available as a PDF file)
- [http://www.afca.org American Football Coaches Association]
- [http://memory.loc.gov/cgi-bin/query/S?ammem/papr:@FILREQ(@field(TITLE+@od1(Chicago-Michigan+football+game++))+@FIELD(COLLID+workleis)) Movie of 1903 football game between the University of Chicago and the University of Michigan]
- [http://www.nfl.com/history/chronology/ Chronology of many events in the NFL]
- [http://www.iwflsports.com The Women's League] ko:미식축구 ja:アメリカンフットボール simple:American football th:อเมริกันฟุตบอล

Shotguns

:This article is about the firearm. For alternative meanings of shotgun, see: Shotgun (disambiguation). Shotgun (disambiguation) A shotgun is a firearm typically used to fire a number of small spherical pellets, the shot, from a smoothbore barrel of relatively large diameter. Compared to many bullets, the energy of any one ball of shot is fairly low, making shotguns useful primarily for hunting birds and other small game, or as close-combat weapons or defensive weapons where the short range ensures that many of the balls of shot will hit the target (see riot shotgun and combat shotgun). Ammunition for shotguns is referred to as shotgun shells, or just shells (when it is not likely to be confused with artillery shells). The shotgun has several advantages over a normal gun. It has enormous stopping power at short range. The wide spread of shot produced by the gun makes it easy to aim and to be used by inexperienced marksmen. Also, shot is less likely to penetrate walls and hit bystanders. It is favored by law enforcement for its low penetration and high stopping power, while many American households use it as a home defense weapon for the same reasons. It should be bourn in mind that the vaunted "wide pattern" of a cylinder/improved cylinder choked shotgun is often much overstated. The typical home defense shot is seldom over ten or fifteen feet. At these relatively short ranges, the shot charge never expands to more than a few inches. You need to be in the twenty to thirty yard range to take advantage of an expanded pattern. At fifteen feet, you'd better have the gun pointed accurately if you intend to hit your target.

Definition

The United States legal code (18 USC 921) defines the shotgun as "a weapon designed or redesigned, made or remade, and intended to be fired from the shoulder, and designed or redesigned and made or remade to use the energy of the explosive in a fixed shotgun shell to fire through a smooth bore either a number of ball shot or a single projectile for each single pull of the trigger." This definition, however, does not exactly match the technical use of the term, which would include the growing number of shotguns specifically designed to fire single projectiles instead of shot. A rifled slug, with finned rifling designed to spin the bullet and stabilize it in order to improve its accuracy, is an example of a single projectile. Some shotguns have rifled barrels and are designed to be used with a "saboted" bullet. A saboted bullet is typically encased in two-piece plastic ring (sabot) which is designed to fall away after it passes the end of the barrel, leaving the bullet, now spinning after passing through the rifled barrel, to continue toward the target. These shotguns, although they have rifled barrels, still use a shotgun-style shell instead of a rifle cartridge. Hunting laws may differentiate between smooth barreled and rifled barreled guns. Also, technically speaking, many people would likely call a fully automatic shotgun a shotgun, even though legally it would fall under a different category. Amongst the general populace, any gun that fires shotgun shells could be considered a shotgun. Riot gun has long been a synonym for a shotgun, especially a short barreled shotgun. During the 19th and early 20th century, short-barreled shotguns were used to disperse rioters and revolutionaries. The wide spray of the shot ensured a large group would be hit, but the light shot would ensure more wounds than fatalities. When the ground was paved, police officers would often richochet the shot off the ground, slowing down the shot and spreading the spray out even further. To this day specialized police and defensive shotguns are called riot shotguns. The introduction of rubber bullets and bean bag rounds ended the practice of using shot for the most part, but riot shotguns are still used to fire a variety of less than lethal rounds for riot control. A sawn-off shotgun refers to a shotgun whose barrel has been shortened, leaving it more manouverable and easier to use at short range, more readily concealed, and more lethal. The sawn-off shotgun is sometimes known as a "Lupara" (In Italian a generic reference to the word "Lupo" ("Wolf") ) in Southern Italy and Sicily.

History

Sicily Shotguns have also been referred to as "scatterguns", "fowling pieces" or "two-shoot guns" historically, and were used as a replacement for the blunderbuss. The first recorded use of the term shotgun was in 1776 in Kentucky. It was noted as part of the "frontier language of the West" by James Fenimore Cooper. During its long history, it has been favored by bird hunters, guards and law enforcement officials. Essentially, early muzzle-loading shotguns were identical to muskets, in that they were both smoothbore weapons that were often used to fire multiple projectiles (see "buck and ball"). However, the musket was generally a longer barreled weapon than a true shotgun. The shotgun has fallen in and out of favor with military forces several times in its long history. Shotguns and similar weapons are simpler than long-range rifles, and were developed earlier. The development of more accurate and deadlier long-range rifles minimized the usefulness of the shotgun on the open battlefields of European wars. But armies have "rediscovered" the shotgun for specialty uses many times.

The 19th century

During the 1800s, shotguns were mainly employed by cavalry units. Cavalry units on both sides of the American Civil War employed shotguns. American cavalry went on to use the shotgun extensively during the Indian Wars throughout the latter half of the 19th century. Horseback units favored the shotgun for its ease of aiming and devastating close range firepower. The shotgun was also favored by citizen militias and similar groups. The shotgun was used in the defense of The Alamo during Texas' War of Independence with Mexico. With the exception of cavalry units, the shotgun saw less and less use throughout the 19th century on the battlefield. It remained popular with guards and lawmen, however. The famous lawman Wyatt Earp killed several men with a shotgun, and express messengers became known as "shotgun messengers", since they rode with them for self defense. During this period, the shotgun became one of many symbols of the American Old West. Contrary to the Hollywood myth, it was the shotgun, in the hands of the settler, that tamed the West, not the sixgun, which took rather more skill.

John Browning

The single most influential man in the modern development of the shotgun was prolific gun designer John Browning. While working for Winchester Firearms, Browning revolutionized shotgun design. In 1887, Browning introduced the Model 1887 Lever Action Repeating Shotgun, which loaded a fresh cartridge from its internal magazine by the operation of the action lever. Before this time, a majority of shotguns were the older muzzle-loading type, or were of the 'break-action' type, which were, apart from double-barrels, non-repeating. This development was greatly overshadowed by two further innovations he introduced at the end of the 19th century. In 1893, Browning produced the Model 1893 Pump Action Shotgun, introducing the now familiar pump action to the market. And in 1900, he patented the Browning Auto-5, the world's first semi-automatic shotgun. To this day, the Auto-5 is considered one of Browning's best designs and is still being produced.

The 20th and 21st centuries

1900 The decline in military use of shotguns reversed in World War 1. American forces under General Pershing employed 12-gauge pump action shotguns when they were deployed to the Western front in 1917. These shotguns were fitted with bayonets and a heat shield so the barrel could be gripped while the bayonet was deployed. Shotguns fitted in this fashion became known as trench guns by the United States Army. Those without such modifications were known as riot guns. After World War 1, the United States military began referring to all shotguns as riot guns. Due to the cramped conditions of trench warfare, the American shotguns were extremely effective. Germany even filed an official diplomatic protest against their use, alleging they violated the laws of warfare. The Judge Advocate General reviewed the protest, and it was rejected. This is the only occasion the legality of the shotgun's use in warfare has been questioned. Judge Advocate General During World War 2, the shotgun was not used heavily in the war in Europe by official military forces. However, the shotgun was a favorite weapon of Allied supported partisans, such as the French Resistance. By contrast, in the Pacific theater, thick jungles and heavily fortified positions made the shotgun a favorite weapon of United States Marines. Marines tended to use pump shotguns, since the pump action was less likely to jam in the humid and dirty conditions of the Pacific campaign. Since the end of World War 2, the shotgun remained a specialty weapon for modern armies. It has been deployed for specialized tasks where its strengths are put to particularly good use. It was used to defend machine gun emplacements during the Korean War, and American and French jungle patrols used shotguns during the Vietnam War. But shotguns are far from being as common amongst military forces as rifles, carbines or submachineguns. On the other hand, the shotgun has become a standard in American law enforcement firearms. Shotguns are standard equipment in most United States police patrol cars, and almost all police officers are trained in their use. A variety of specialty ammunition, such as tear gas shells, are produced specifically for the law enforcement market. While shotguns, especially sawn-off shotguns, have received a reputation for criminal use, this is mainly a misconception. In 1994, shotguns consisted of only 9.7% of gun traces relating to a criminal investigation in the United States, and were the weapon of choice in only 5% of homicides. Shotguns are not the preferred weapons for criminal activity, since criminals prefer weapons which are easily concealed, according to the National Crime Victimization Survey.

Design factors

Vietnam War

Action

Action is

Rifle

Overview

History

History of design

History of use

See also

Kinds of rifles

External links

Firearm

Small arms

Handguns

Long guns

Machine guns

Loading and firing mechanisms

Cannon

Muzzleloader

Matchlock

Wheellock

Flintlock

Percussion cap

Cartridges

Repeating, semiautomatic, and automatic weapons

See also

See also

Gun technology and science

Guns and society

Gun-related terminology

Lists of weapons

Types

WW II Era

Other

Manufacturers

External resources

External links

Bullet

Material

Design

Types

Manufacture

Lead bullets

Jacketed bullets

Treaties

History

The first bullets

The bullet takes shape

The modern bullet

Bullet acronyms

See also

American football

Popularity

The rules of American football

Field and players

Game duration

Advancing the ball

Changes of possession

Scoring

Kickoffs and free kicks

The players

Offense

Defense

Special teams

Basic football strategy

Development of the game

Problems in Football

Professional, college, and other leagues

References

See also

External links

Shotguns

Definition

History

The 19th century

John Browning

The 20th and 21st centuries

Design factors

Action