出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/06/10 02:53:08」(JST)
A firearm is a portable gun, being a barreled weapon that launches one or more projectiles often driven by the action of an explosive force.[1][2][3] The first primitive firearms were invented in 13th century China when the man portable fire lance (a bamboo or metal tube that could shoot ignited gunpowder) was combined with projectiles such as scrap metal, broken porcelain, or darts/arrows.[4] The technology gradually spread through the rest of East Asia, South Asia, Middle East and then into Europe. In older firearms, the propellant was typically black powder, but modern firearms use smokeless powder or other propellants. Most modern firearms (with the notable exception of smoothbore firearms) have rifled barrels to impart spin to the projectile for improved flight stability.
Modern firearms are typically described by their bore diameter (7.5mm) or calibre (.357) or gauge (12 ga.), the type of action employed (muzzle, breech, lever, bolt, pump, revolver, semi-automatic, or automatic) together with the usual means of deportment (hand-held or mechanical mounting). They may be further distinguished by reference to the type of barrel used (rifled) and the barrel length (19 inch), the design's primary intended target (anti-aircraft), or the commonly accepted name for a particular variation (Gatling gun).
Firearms may sometimes be referred to as small arms when they are intended primarily for use by military forces if they can be carried by a single individual.
Firearms are aimed visually at their targets by hand using either iron sights or optical sights. The accurate range of pistols is generally limited to 50 metres (55 yd), while most rifles are accurate to 500 metres (550 yd) using iron sights, or longer ranges using optical sights. (Firearm rounds may be dangerous or lethal well beyond their accurate range; minimum distance for safety is much greater than specified range.) Some purpose-built sniper rifles are accurate to ranges of more than 2,000 metres (2,200 yd). A successful sniper attack has been made from slightly more than 1.75 mi (2.82 km).
The manufacture of firearms is a global industry. According to the National Shooting Sports Foundation (N.S.S.F.), a trade association for the US firearms industry, all economic activity from firearm manufacturing, distribution, and other ancillary activities totaled US$27.8 billion in 2010 in the United States.[5]
The smallest of all firearms is the handgun. There are three common types of handguns: single-shot pistols (more common historically), revolvers, and semi-automatic pistols. Revolvers have a number of firing chambers or "charge holes" in a revolving cylinder; each chamber in the cylinder is loaded with a single cartridge or charge. Semi-automatic pistols have a single fixed firing chamber machined into the rear of the barrel, and a magazine so they can be used to fire more than one round. Each press of the trigger fires a cartridge, using the energy of the cartridge to activate the mechanism so that the next cartridge may be fired immediately. This is opposed to "double-action" revolvers which accomplish the same end using a mechanical action linked to the trigger pull.
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. Certain designs of auto-loading pistol appeared beginning in the 1870s and had largely supplanted revolvers in military applications by the end of World War I. By the end of the 20th century, most handguns carried regularly by military, police and civilians were semi-automatic, although revolvers were still widely used. Generally speaking, military and police forces use semi-automatic pistols due to their high magazine capacities (10 to 17 or, in some cases, over 25 rounds of ammunition) and ability to rapidly reload by simply removing the empty magazine and inserting a loaded one. Revolvers are very common among handgun hunters because revolver cartridges are usually more powerful than similar caliber semi-automatic pistol cartridges (which are designed for self-defense) and the strength, simplicity and durability of the revolver design is well-suited to outdoor use. Revolvers, especially in .22LR and 38 Special/357 Magnum, are also common concealed weapons in jurisdictions allowing this practice because their simple mechanics make them smaller than many autoloaders while remaining reliable. Both designs are common among civilian gun owners, depending on the owner's intention (self-defense, hunting, target shooting, competitions, collecting, etc.).
A long gun is generally any firearm that is larger than a handgun and is designed to be held and fired with both hands, either from the hip or the shoulder. Long guns typically have a barrel between 10 and 30 inches (there are restrictions on minimum barrel length in many jurisdictions; maximum barrel length is usually a matter of practicality), that along with the receiver and trigger group is mounted into a wood, plastic, metal or composite stock, composed of one or more pieces that form a foregrip, rear grip, and optionally (but typically) a shoulder mount called the butt. Early long arms, from the Renaissance up to the mid-1800s, were generally smoothbore firearms that fired one or more ball shot, called muskets.
Most modern long guns are either rifles or shotguns. Both are the successors of the musket, diverging from their parent weapon in distinct ways. A rifle is so named for the spiral fluting (Rifling) carved into the inner surface of its barrel, which imparts a self-stabilizing spin to the single bullets it fires. Shotguns are predominantly smoothbore firearms designed to fire a number of shot; pellet sizes commonly ranging between 2 mm #9 birdshot and 8.4 mm #00 (double-aught) buckshot. Shotguns are also capable of firing single slugs, or specialty (often "less lethal") rounds such as bean bags, tear gas or breaching rounds. 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 generally used for flying game (See Spreading details).
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, particularly with slugs), while birds are hunted with shotguns. Shotguns are sometimes preferred for defending a home or business due to their wide impact area, multiple wound tracks (when using buckshot), shorter range, and reduced penetration of walls (when using lighter shot), which significantly reduces the likelihood of unintended harm, although the handgun is also common.
There are a variety of types of rifles and shotguns based on the method they are reloaded. Bolt-action and lever-action rifles are manually operated. Manipulation of the bolt or the lever causes the spent cartridge to be removed, the firing mechanism recocked, and a fresh cartridge inserted. These two types of action are almost exclusively used by rifles. Slide-action (commonly called 'pump-action') rifles and shotguns are manually cycled by shuttling the foregrip of the firearm back and forth. This type of action is typically used by shotguns, but several major manufacturers make rifles that use this action.
Both rifles and shotguns also come in break-action varieties that do not have any kind of reloading mechanism at all but must be hand-loaded after each shot. Both rifles and shotguns come in single- and double-barreled varieties; however due to the expense and difficulty of manufacturing, double-barreled rifles are rare. Double-barreled rifles are typically intended for African big-game hunts where the animals are dangerous, ranges are short, and speed is of the essence. Very large and powerful calibers are normal for these firearms.
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 American Revolutionary War. 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 1 mile (1,600 m), although most have considerably less. 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.
In military use, bolt-action rifles with high-power scopes are common as sniper rifles, however by the Korean War the traditional bolt-action and semi-automatic rifles used by infantrymen had been supplemented by select-fire designs known as "automatic rifles" (see "Automatic Rifle" below).
A carbine is a firearm similar to a rifle in form and intended usage, but generally shorter or smaller than the typical "full-size" hunting or battle rifle of similar time period, and sometimes using a smaller or less-powerful cartridge. Carbines were and are typically used by members of the military in roles that are expected to engage in combat, but where a full-size rifle would be an impediment to the primary duties of that soldier (vehicle drivers, field commanders and support staff, airbornes, engineers, etc.). Carbines are also common in law enforcement and among civilian owners where similar size, space and/or power concerns may exist. Carbines, like rifles, can be single-shot, repeating-action, semi-automatic or select-fire/fully automatic, generally depending on the time period and intended market. Common historical examples include the Winchester Model 1892, Lee-Enfield "Jungle Carbine", Mauser K98 Kurz, SKS, M1 carbine (no relation to the larger M1 Garand) and M4 carbine (a more compact variant of the current M16 rifle). Modern U.S. civilian carbines include compact customizations of the AR-15, Ruger Mini-14, Beretta Cx4 Storm, Kel-Tec SUB-2000, bolt-action rifles generally falling under the specifications of a scout rifle, and aftermarket conversion kits for popular pistols including the M1911 and Glock models.
Firearms are also categorized by their functioning cycle or "action" which describes its loading, firing, and unloading cycle.
The earliest evolution of the firearm, there are man types of manual action firearms. These can be divided into two basic categories: single shot and repeating.
A single shot firearm can only be fired once per equipped barrel before it must be reloaded or charged via an external mechanism or series of steps. A repeating firearm can be fired multiple times, but can only be fired once with each subsequent pull of the trigger. Between trigger pulls, the firearm's action must be reloaded or charged via an internal mechanism.
A semi-automatic, or self-loading, firearm is one that performs all steps necessary to prepare the it to discharge again after firing—assuming cartridges remain in the weapon's feed device or magazine.
An automatic firearm is generally defined as one that continues to load and fire cartridges from its magazine as long as the trigger is depressed (or until the magazine is depleted). The first weapon generally considered in this category is the Gatling gun, originally a carriage-mounted, crank-operated firearm with multiple rotating barrels that was fielded in the American Civil War. The modern trigger-actuated machine gun began with various designs developed in the late 1800s and fielded in World War I, such as the Maxim gun, Lewis Gun, and MG 08 "Spandau". Most automatic weapons are classed as long guns (as the ammunition used is of similar type as for rifles, and the recoil of the weapon's rapid fire is better controlled with two hands), but handgun-sized automatic weapons also exist, generally in the "submachine gun" or "machine pistol" class.
A machine gun is a fully automatic emplaceable weapon, most often separated from other classes of automatic weapon by the use of belt-fed ammunition (though some designs employ drum, pan or hopper magazines), generally in a rifle-inspired caliber ranging between 5.56×45mm NATO (.223 Remington) for a light machine gun to as large as .50 BMG or even larger for crewed or aircraft weapons. Although not widely fielded until World War I, early machine guns were being used by militaries in the second half of the 19th century. Notables in the U.S. arsenal during the 20th century included the M2 Browning .50 caliber heavy machine gun and M1919 Browning .30 caliber medium machine gun, and the M60 7.62×51mm NATO general-purpose machine gun which came into use around the Vietnam War. Machine guns of this type were originally defensive firearms crewed by at least two men, mainly because of the difficulties involved in moving and placing them, their ammunition, and their tripod. In contrast, modern light machine guns such as the FN Minimi are often wielded by a single infantryman. They provide a large ammunition capacity and a high rate of fire, and are typically used to give suppressing fire during infantry movement. Accuracy on machine guns varies based on a wide number of factors from design to manufacturing tolerances, most of which have been improved over time. Machine guns are often mounted on vehicles or helicopters, and have been used since World War I as offensive firearms in fighter aircraft and tanks (e.g. for air combat or suppressing fire for ground troop support).
The definition of machine gun is different in U.S. law. The National Firearms Act and Firearm Owners Protection Act define a "machine gun" in the United States code Title 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as: "... any firearm which shoots ... automatically more than one shot, without manual reloading, by a single function of the trigger". "Machine gun" is therefore largely synonymous with "automatic weapon" in the U.S. civilian parlance, covering all automatic firearms.
A submachine gun is a magazine-fed firearm, usually smaller than other automatic firearms, that fires pistol-caliber ammunition; for this reason certain submachine guns can also be referred to as machine pistols, especially when referring to handgun-sized designs such as the Škorpion vz. 61 and Glock 18. Well-known examples are the Israeli Uzi and Heckler & Koch MP5 which use the 9×19mm Parabellum cartridge, and the American Thompson submachine gun which fires .45 ACP. Because of their small size and limited projectile penetration compared to high-power rifle rounds, submachine guns are commonly favored by military, paramilitary and police forces for close-quarters engagements such as inside buildings, in urban areas or in trench complexes.
Submachine guns were originally about the size of carbines. Because they fire pistol ammunition, they have limited long-range use, but in close combat can be used in fully automatic in a controllable manner due to the lighter recoil of the pistol ammunition. They are also extremely inexpensive and simple to build in time of war, enabling a nation to quickly arm its military. 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 Maschinenpistole 5, or Machine Pistol 5), although some reserve this designation for even smaller submachine guns such as the MAC-10 and Glock 18, which are about the size and shape of pistols.
A related class of firearm to the submachine gun is the "Personal Defense Weapon" or PDW, which is in simplest terms a submachine gun designed to fire rounds similar to rifle cartridges. A submachine gun is desirable for its compact size and ammunition capacity, however a pistol round lacks the penetrating capability of a rifle round. Conversely, rifle bullets can pierce light armor and are easier to shoot accurately, but even a carbine such as the Colt M4 is larger and/or longer than a submachine gun, making it harder to maneuver in close quarters. The solution many firearms manufacturers have presented is a weapon resembling a submachine gun in size and general configuration, but which fires a higher-powered armor-penetrating round (often specially designed for the weapon), thus combining the advantages of a carbine and submachine gun. The FN P90 and Heckler & Koch MP7 are examples.
An automatic rifle is a magazine-fed firearm, wielded by a single infantryman, that is chambered for rifle cartridges and capable of automatic fire. The M1918 Browning Automatic Rifle was the first U.S. infantry weapon of this type, and was generally used for suppressive or support fire in the role now usually filled by the light machine gun. Other early automatic rifles include the Fedorov Avtomat and the Huot Automatic Rifle. Later, German forces fielded the Sturmgewehr 44 during World War II, a light automatic rifle firing a reduced power "intermediate cartridge". This design was to become the basis for the "assault rifle" subclass of automatic weapons, as contrasted with "battle rifles", which generally fire a traditional "full-power" rifle cartridge.
In World War II, Germany brought to the forefront of firearm technology what eventually became the class of firearm most widely adopted by the military: the assault rifle (see StG 44). An assault rifle is usually slightly smaller than a battle rifle such as the Karabiner 98k, but the chief differences defining an assault rifle are select-fire capability and the use of a rifle round of lesser power, known as an intermediate cartridge. This reduces recoil allowing for controllable bursts at short range like a submachine gun, while retaining rifle-like accuracy at medium ranges. Generally, assault rifles have mechanisms that allow the user to select between single shots, fully automatic bursts, or fully automatic fire. Universally, civilian versions of military assault rifles are strictly semi-automatic.
Soviet engineer Mikhail Kalashnikov quickly adapted the German concept, using a less-powerful 7.62×39mm cartridge derived from the standard 7.62×54mmR Russian battle rifle round, to produce the AK-47, which has become the world's most widely used assault rifle. Soon after World War II, the Automatic Kalashnikov AK-47 assault rifle began to be fielded by the Soviet Union and its allies in the Eastern Bloc, as well as by nations such as China, North Korea, and North Vietnam.
In the United States, the assault rifle design was later in coming; the replacement for the M1 Garand of WWII was another John Garand design chambered for the new 7.62×51mm NATO cartridge; the select-fire M14, which was used by the U.S. military until the 1960s. The significant recoil of the M14 when fired in full-automatic mode was seen as a problem as it reduced accuracy, and in the 1960s it was replaced by Eugene Stoner's AR-15, which also marked a switch from the powerful .30 caliber cartridges used by the U.S. military up until early in the Vietnam War to the much less powerful but far lighter and light recoiling .223 caliber (5.56mm) intermediate cartridge. The military later designated 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 to conform to B.A.T.F.E. regulations in the U.S., it lacks the mechanism that permits fully automatic fire.
Variants of both of the M16 and AK-47 are still in wide international use today, though other automatic rifle designs have since been introduced. A smaller version of the M16A2, the M4 carbine, is widely used by U.S. and NATO tank and vehicle crews, airbornes, support staff, and in other scenarios where space is limited. The IMI Galil, an Israeli-designed weapon similar to the AK-47, is in use by Israel, Italy, Burma, the Philippines, Peru, and Colombia. Swiss Arms of Switzerland produces the SIG SG 550 assault rifle used by France, Chile, and Spain among others, and Steyr Mannlicher produces the AUG, a bullpup rifle in use in Austria, Australia, New Zealand, Ireland, and Saudi Arabia among other nations.
Modern designs call for compact weapons retaining firepower. The bullpup design, by mounting the magazine behind the trigger, unifies the accuracy and firepower of the traditional assault rifle with the compact size of the submachine gun (though submachine guns are still used); examples are the French FAMAS or the British SA80. Recently, smaller but exceedingly penetrative ammunition types have been introduced to allow countermeasure against ballistic armour. Such designs are the basis for the FN P90 and Heckler & Koch MP7. Caseless ammunition is another trend; an example is the German Heckler & Koch G11. The flechette is yet another improvement over traditional ammunition, allowing for extreme penetration abilities and a very flat trajectory. However, it is gained at the cost of stopping power.
The earliest depiction of a firearm is a sculpture from a cave in Sichuan, China. The sculpture dates to the 12th century and is of a figure carrying a vase-shaped bombard, with flames and a cannonball coming out of it.[6] The oldest surviving gun, made of bronze, has been dated to 1288 because it was discovered at a site in modern-day Acheng District, Heilongjiang, China, where the Yuan Shi records that battles were fought at that time.[7] The firearm had a 6.9 inch barrel of a 1 inch diameter, a 2.6 inch chamber for the gunpowder and a socket for the firearm's handle. It is 13.4 inches long and 7.8 pounds without the handle, which would have been made of wood.[8]
The Europeans and Arabs obtained firearms in the 14th century.[8] The Turks, Iranians, and Indians all had firearms no later than the 15th century, in each case directly or indirectly from the Europeans.[8] The Japanese did not acquire firearms until the 16th century, and then from the Portuguese rather than the Chinese.[8]
The development behind firearms accelerated during the 1800s and 1900s. Breech-loading became more or less a universal standard for the reloading of most hand-held firearms and continues to be so with some notable exceptions (such as mortars). Instead of loading individual rounds into weapons, magazines holding multiple munitions were adopted—these aided rapid reloading. Automatic and semi-automatic firing mechanisms meant that a single soldier could fire many more rounds in a minute than a vintage weapon could fire over the course of a battle. Polymers and alloys in firearm construction made weaponry progressively lighter and thus easier to deploy. Ammunition changed over the centuries from simple metallic ball-shaped projectiles that rattled down the barrel to bullets and cartridges manufactured to high precision. Especially in the past century has particular attention been devoted to accuracy and sighting to make firearms altogether far more accurate than ever before. More than any single factor though, firearms have proliferated due to the advent of mass production—enabling arms manufacturers to produce large quantities of weaponry to a consistent standard.
The force of a projectile is related to the kinetic energy (KE) imparted to it, given by the formula: Kinetic Energy = 0.5*M*V^2 where M=Mass and V=Velocity
Historically, KE has been enhanced in two ways:
The first way the KE was enhanced was increasing the "caliber" of the weapon. Caliber refers to the diameter of the bore of the barrel, given in decimal fractions of an inch or, in metric systems, in millimeters. Thus, a handgun or rifle could be referred to as .45 cal or .38 cal (called 45 caliber or 38 caliber) or 9mm.
The second way modern weapons increase KE is through velocity, as impelled by modern gunpowder, which increases the force tremendously because it increases KE as a square of any increment of improvement in velocity.
Velocities of bullets increased with the use of a "jacket" of a metal such as copper or copper alloys that covered a lead core and allowed the bullet to glide down the barrel more easily than exposed lead. Such bullets are designated as "full metal jacket" (FMJ). Such FMJ bullets are less likely to fragment on impact and are more likely to traverse through a target while imparting less energy. Hence, FMJ bullets impart less tissue damage than non-jacketed bullets that expand. (Dougherty and Eidt, 2009) This led to their adoption for military use by countries adhering to the Hague Convention in 1899.
That said, the basic principle behind firearm operation remains unchanged to this day. A musket of several centuries ago is still similar in principle to a modern-day assault rifle—using the expansion of gases to propel projectiles over long distances—albeit less accurately and rapidly.
The Chinese fire lance was the direct predecessor to the modern concept of the firearm. It was not a gun itself, but an addition to the soldiers' spears. Originally it consisted of paper or bamboo barrels that would have incendiary gunpowder within it, that could be lit one time and would project flames at the enemy. Sometimes the Chinese troops would place small projectiles within the barrel that would also be projected when the gunpowder was lit, but most of the explosive force would create flames. Later, the barrel was changed to be made of metal, so that a more explosive gunpowder could be used and put more force into the propulsion of the projectile.[8]
The original predecessor of all firearms, the Chinese fire lance and European hand cannon were loaded with gunpowder and the shot (initially lead shot, later replaced by cast iron[citation needed]) through the muzzle, while a fuse was placed at the rear. This fuse was lit, causing the gunpowder to ignite and propel the cannonball. In military use, the standard hand cannon was tremendously powerful, while also being somewhat useless[citation needed] due to relative inability of the gunner to aim the weapon, or control the ballistic properties of the projectile. Recoil could be absorbed by bracing the barrel against the ground using a wooden support, the forerunner of the stock. Neither the amount of gunpowder, nor the consistency in projectile dimensions were controlled, with resulting inaccuracy in firing due to windage, and due to the difference in diameter between the bore and the shot. The hand cannons were replaced by lighter carriage-mounted artillery pieces, and ultimately the arquebus.
Muzzle-loading muskets (smooth-bored long guns) were among the first firearms 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 firearm to the person attempting to fire it.
One interesting solution to the reloading problem was the "Roman Candle Gun" with superposed loads. 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.[9]
| This section requires expansion. (March 2012) |
Most early fire arms were muzzle-loading. This form of loading has several disadvantages, such as a slower rate of fire and having to expose oneself to enemy fire to reload. As manufacturing processes improved, breech-loading weapons eventually replaced these weapons.
Breech-loading weapons came much later, as effective methods of sealing the breech were developed. The first breech-loading weapons were swivel guns used in naval warfare. These were first created in the 14th century, although the design was not applied to firearms until the 16th century. Eventually they superseded muzzle-loading weapons. As self-loading weapons were produced, the earlier forms became obsolete although they do remain in most artillery.
Many firearms made in the late 19th century through the 1950s used internal magazines to load the cartridge into the chamber of the weapon. This internal magazine could not be removed from the weapon without dissembling the weapon itself. These magazines are loaded while they are in the weapon, often using a stripper clip. A clip is used to transfer cartridges into the magazine. Some notable weapons that use internal magazines include the M1 Garand, the SKS, the Springfield M1903, the Mosin Nagant, and the Mauser C96 to name few. Firearms that have internal magazines are usually, but not always, rifles. Some exceptions to this include the Mauser C96 pistol, which uses an internal magazine, and the Breda 30, an Italian Light Machine Gun.
Many modern firearms use what are called detachable or box magazines as their method of chambering a cartridge. Detachable magazines can be removed from the weapon without disassembling the firearms, usually by pushing the magazine release. Some notable weapons that use detachable magazines include the M14, the AR-15, the Glock 17, and the AK-47.
A belt or ammunition belt is a device used to retain and feed cartridges into a firearm commonly used on machine guns. Belts were originally composed of canvas or cloth with pockets spaced evenly to allow the belt to be mechanically fed into the gun. These designs were prone to malfunctions due to the effects of oil and other contaminants altering the belt. Later belt designs used permanently connected metal links to retain the cartridges during feeding. These belts were more tolerant to exposure to solvents and oil. Some notable weapons that use belts are the M240, the M249, the M134 Minigun, and the PK Machine Gun.
Matchlocks were the first and simplest firearms 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.The main parts to the matchlock firing mechanism are the pan, match, arm and trigger.[10] A benefit of the pan and arm swivel being moved to the side of the gun was it gave a clear line of fire.[11] An advantage to the matchlock firing mechanism is that it did not misfire. However, it also came with some disadvantages. One disadvantage was if it was raining the match could not be kept lit to fire the weapon. Another issue with the match was it could give away the position of soldiers because of the glow, sound, and smell.[12]
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 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 wheellock action was an innovation that was not widely adopted due to the high cost of the clockwork mechanism.
The flintlock action was a major innovation in firearm 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 referred 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 Lock) The flintlock was widely used during the 18th and 19th centuries in both muskets and rifles.
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 firearms 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 firearms.
A major innovation in firearms 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 (usually brass) cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. The main technical advantage of the brass cartridge case was the effective and reliable sealing of high pressure gasses at the breech, as the gas pressure forces the cartridge case to expand outward, pressing it firmly against the inside of the gun barrel chamber. This prevents the leakage of hot gas which could injure the shooter. The brass cartridge also opened the way for modern repeating arms, by uniting the bullet, gunpowder and primer into one assembly that could be fed reliably into the breech by a mechanical action in the firearm.
Before this, a "cartridge" was simply a premeasured quantity of gunpowder together with a ball in a small cloth bag (or rolled paper cylinder), 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, operating at considerably higher pressures than rimfire cartridges. Centerfire cartridges are also safer, as a dropped rimfire cartridge has the potential to discharge if its rim strikes the ground with sufficient force to ignite the primer. This is practically impossible with most centerfire cartridges.
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 defined as a part of the firearm which exists to store ammunition and assist in its feeding by the action into the breech (such as through the rotation of a revolver's cylinder or by spring-loaded platforms in most pistol and rifle designs). Some magazines, such as that of most centerfire hunting rifles and all revolvers, are internal to and inseparable from the firearm, and are loaded by using a "clip". A clip, often mistakingly used to refer to a detachable "magazine", is a device that holds the ammunition by the rim of the case and is designed to assist the shooter in reloading the firearm's magazine. Examples include revolver speedloaders, the stripper clip used to aid loading rifles such as the Lee-Enfield or Mauser 98, and the en-bloc clip used in loading the M1 Garand. In this sense, "magazines" and "clips", though often used synonymously, refer to different types of devices.
Many firearms are "single shot": i.e., each time a cartridge is fired, the operator must manually re-cock the firearm and load another cartridge. The classic single-barreled shotgun is a good example. A firearm that can load multiple cartridges as the firearm is re-cocked is considered a "repeating firearm" or simply a "repeater". A lever-action rifle, a pump-action shotgun, and most bolt-action rifles are good examples of repeating firearms. A firearm that automatically re-cocks and reloads the next round with each trigger pull is considered a semi-automatic or autoloading firearm.
The first "rapid firing" firearms 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, thus the operator needed only to pull a trigger (which made the firing mechanisms truly "automatic"). An automatic (or "fully automatic") firearm is one that automatically re-cocks, reloads, and fires as long as the trigger is depressed. An automatic firearm is capable of firing multiple rounds with one pull of the trigger. The Gatling gun may have been the first automatic weapon, though the modern trigger-actuated machine gun was not widely introduced until the First World War with the German "Spandau" and British Lewis Gun. Automatic rifles such as the Browning Automatic Rifle 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. Many modern military firearms have a selective fire option, which is a mechanical switch that allows the firearm be fired either in the semi-automatic or fully automatic mode. In the current M16A2 and M16A4 variants of the U.S.-made M16, continuous fully automatic fire is not possible, having been replaced by an automatic burst of three cartridges (this conserves ammunition and increases controllability).
Automatic weapons are largely restricted to military and paramilitary organizations, though many automatic designs are infamous for their use by civilians. Automatic firearms have long been available to U.S. civilians, under increasingly restrictive conditions. Importation of machine guns for civilian sale in the U.S. was banned by the Gun Control Act of 1968. The Hughes Amendment to the Firearm Owners Protection Act now prohibits United States civilian ownership or transfer of automatic weapons unless they were registered before May 19, 1986. Non-prohibited automatic weapons can be legally owned by civilians who pay a $200 tax to the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE), pass a background investigation, and, in some jurisdictions, receive approval from local law enforcement. Permission must be received directly from the BATFE to move a machine gun between states, even if it does not change ownership. An extremely limited number of U.S. citizens have special permits from the BATFE to buy, and even import, automatic weapons produced and registered after 1986. The use of such weapons is tightly restricted to the film industry[citation needed] under direct supervision of the master of arms holding the permit, and the weapons are often altered so they will not fire "factory" ammunition, but rather only special "light-primer" blank cartridges produced specifically for the film industry. This arrangement allows weapons first produced after 1986 to be used by actors in films and T.V. series produced inside the U.S.
The legality of the possession and use of firearms is widely dependent on jurisdiction, type of firearm, and type of ammunition.
In the United States, possession and use of firearms is a recognized right, protected by the Second Amendment to the United States Constitution. Residents of the U.S. are generally allowed to own firearms, keep them in their homes, and use them for recreational purposes or for necessary personal defense. However, courts and various levels of government have indicated that the right is not without limit, and restrictions such as a prohibition of certain persons from owning or handling a gun (convicted felons, mentally ill persons, persons under a restraining order), a ban on certain types of ammunition (armor-piercing, incendiary/tracer, explosive), registration and restriction of certain types of firearms (automatic weapons, short-barrelled shotguns, certain types of modifications), and licensing requirements for possession or for public carry, have often passed judicial scrutiny (although some of these points remain untested and others are currently under challenge).
In the U.K., firearms law generally prohibits the ownership of virtually all handguns and semi-automatic or repeating-action centerfire rifles, as well as machine guns, rocket launchers, grenades etc. Rimfire rifles such as .22s are generally legal, as are shotguns of any type provided the firearm cannot hold more than three rounds. Legal possession of a firearm requires a Firearm Certificate or Shotgun Certificate (depending on the type of weapon). Case law in the United Kingdom generally makes it a crime to cause the death of another person by any means, with little or no provision for justifiable homicide. Firearms are kept primarily for sporting purposes including range shooting and hunting.
In continental Europe, attitudes on gun regulation by governments varies widely. Western European nations tend to have more restrictions on gun ownership and use than Eastern European nations. One notable exception to this general trend, Switzerland, mandates the possession of a personal, government-issued firearm by members of the militia (typically males between 20 and 30). Possession of a fully automatic firearm is prohibited in virtually all European countries except for members of the military/militia and collectors.
In the Middle East, gun laws again vary, but are generally restrictive among Arab nations, with most countries banning civilian ownership of firearms. Despite this, arms smuggling is rampant and black-market small arms, usually Russian-made, are bought and sold by various non-government organizations ranging from paramilitary groups to terrorist organizations. Israel does not recognize the possession of firearms as a right, and requires a license for the possession of a gun, however the circumstances in which one is eligible for a license are generally broader than most surrounding states. A license typically allows the holder to carry one handgun, in some cases a long gun, and residents in certain settlements such as the West Bank are issued firearms by the government and given civil defense training.
In most of central and southern Asia, firearms ownership is very tightly restricted. In China, firearms ownership is generally prohibited, with certain exceptions made for government agents including the military, sport shooters and farmers. Japan prohibits handguns entirely and long guns are restricted to shotguns and single-shot or semi-automatic rifles holding up to no more than five rounds within the magazine. Fully automatic firearms are restricted to law enforcement and the Self-Defense Forces
| Wikimedia Commons has media related to Firearms. |
|
||||||||||||||||||||||||||||||
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
| リンク元 | 「shotgun」「銃砲」 |