Rifling is the term for helical grooves machined into the internal surface of a firearms 's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such grooves.
104-602: Lithgow Arms is an Australian small arms manufacturer located in the town of Lithgow, New South Wales . Established by the Australian Government in 1912 as the Lithgow Small Arms Factory to ease reliance on the British for the supply of defence materials, it is currently owned by Thales Australia . Opened on 8 June 1912, the factory initially manufactured SMLE III rifles (and Pattern 1907 bayonets ) for
208-553: A retronym to differentiate older full-powered rifles of these configurations like the M1 Garand , from newer assault rifles using intermediate cartridges like the Heckler & Koch HK33 , but it is sometimes used to describe similar modern rifles such as the FN SCAR . Battle rifles serve similar purposes as assault rifles, as they both are usually employed by ground infantry for essentially
312-445: A riot gun or breaching rounds to function as a door breaching shotgun. Shotgun munitions, regardless of type, are packed into shotgun shells (cartridges designed specifically for shotguns) that are loaded into the shotgun for use; these shells are commonly loose and manually loaded one-by-one, though some shotguns accept magazines. Shotguns share many qualities with rifles, such as both being descendants of early long guns such as
416-408: A smoothbore barrel without a reduction in accuracy. Muskets are smoothbore , large caliber weapons using ball-shaped ammunition fired at relatively low velocity. Due to the high cost, great difficulty of precision manufacturing, and the need to load readily and speedily from the muzzle, musket balls were generally a loose fit in the barrels. Consequently, on firing the balls would often bounce off
520-663: A broad class of rifles generally summed up as short, lightweight, portable sniper rifles; and designated marksman rifles , semi-automatic high-precision rifles, usually chambered in intermediate or full-power cartridges, that fill the range gap between sniper rifles and regular rifles and are designed for designated marksmen in squads. Examples of sniper and scout rifles include the M40 rifle , Heckler & Koch PSG1 , Walther WA 2000 , Accuracy International AWM , M24 Sniper Weapon System , Steyr Scout , Sako TRG , and CheyTac Intervention . Examples of anti-materiel and anti-tank rifles include
624-419: A consistent unit of measure, i.e. metric (mm) or imperial (in). The third method simply reports the angle of the grooves relative to the bore axis, measured in degrees. The latter two methods have the inherent advantage of expressing twist rate as a ratio and give an easy understanding if a twist rate is relatively slow or fast even when comparing bores of differing diameters. In 1879, George Greenhill ,
728-588: A diameter of 0.5 inches (13 mm) and a length of 1.5 inches (38 mm), the Greenhill formula would give a value of 25, which means 1 turn in 25 inches (640 mm). Improved formulas for determining stability and twist rates include the Miller Twist Rule and the McGyro program developed by Bill Davis and Robert McCoy. If an insufficient twist rate is used, the bullet will begin to yaw and then tumble; this
832-423: A full-power caliber and a certain weight that can be operated by an individual but tend to work best with a crew; and heavy machine guns , machine guns that are too large and heavy to be carried and are thus mounted to something (like a tripod or military vehicle ), and require a crew to operate. A general-purpose machine gun combines these categories under a single flexible machine gun platform, often one that
936-625: A full-size rifle with a shortened carbine-style barrel for close-quarters use. The small size of a carbine provides lighter weight and better maneuverability, making them ideal for close-quarters combat and storage in compact areas. This makes them popular firearms among special forces and police tactical units alongside submachine guns , considerably so since the late 1990s due to the familiarity and better stopping power of carbines compared to submachine guns. They are also popular with (and were originally mostly intended for) military personnel in roles that are expected to engage in combat, but where
1040-452: A full-size rifle would be an impediment to the primary duties of that soldier ( logistical personnel, airborne forces , military engineers , officers , etc.), though since the turn of the millennium these have been superseded to a degree in some roles by personal defense weapons . Carbines are also common among civilian firearm owners who have size, space, and power concerns similar to military and police users. Examples of carbines include
1144-793: A method of effective self-defense against skirmishers and infiltrators who cannot effectively be defeated by low-powered submachine guns and handguns, often the only firearms suitable for those personnel (while they could be issued rifles or carbines, those would become unnecessary burdens in their normal duties, during which the likelihood of hostility is fairly rare regardless, making their issuance questionable). Thus, per their name, personal defense weapons allow these personnel to effectively defend themselves from enemies and repel attacks themselves or at least until support can arrive. They are not intended for civilian self-defense due to their nature as automatic firearms (which are usually prohibited from civilian purchase), though some semi-automatic PDWs exist for
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#17328561354801248-469: A pre-drilled barrel was to use a cutter mounted on a square-section rod, accurately twisted into a spiral of the desired pitch, mounted in two fixed square-section holes. As the cutter was advanced through the barrel it twisted at a uniform rate governed by the pitch. The first cut was shallow. The cutter points were gradually expanded as repeated cuts were made. The blades were in slots in a wooden dowel which were gradually packed out with slips of paper until
1352-660: A professor of mathematics at the Royal Military Academy (RMA) at Woolwich , London, UK developed a rule of thumb for calculating the optimal twist rate for lead-core bullets. This shortcut uses the bullet's length, needing no allowances for weight or nose shape. The eponymous Greenhill Formula , still used today, is: twist = C D 2 L × S G 10.9 {\displaystyle {\text{twist}}={\frac {CD^{2}}{L}}\times {\sqrt {\frac {\mathrm {SG} }{10.9}}}} where C {\displaystyle C}
1456-482: A projectile determines the twist rate needed to gyroscopically stabilize it: barrels intended for short, large-diameter projectiles such as spherical lead balls require a very low twist rate, such as 1 turn in 48 inches (122 cm). Barrels intended for long, small-diameter projectiles, such as the ultra-low-drag 80- grain 0.223 inch bullets (5.2 g, 5.56 mm), use twist rates of 1 turn in 8 inches (20 cm) or faster. Rifling which increases
1560-414: A rifled or smooth bore, a good fit was needed to seal the bore and provide the best possible accuracy from the gun. To ease the force required to load the projectile, these early guns used an undersized ball, and a patch made of cloth, paper, or leather to fill the windage (the gap between the ball and the walls of the bore). The patch acted as a wadding and provided some degree of pressure sealing , kept
1664-638: A round ball; these will have twist rates as low as 1 in 72 inches (180 cm), or slightly longer, although for a typical multi-purpose muzzleloader rifle, a twist rate of 1 in 48 inches (120 cm) is very common. The M16A2 rifle, which is designed to fire the 5.56×45mm NATO SS109 ball and L110 tracer bullets, has a 1 in 7-inch (18 cm) or 32 calibers twist. Civilian AR-15 rifles are commonly found with 1 in 12 inches (30 cm) or 54.8 calibers for older rifles and 1 in 9 inches (23 cm) or 41.1 calibers for most newer rifles, although some are made with 1 in 7 inches (18 cm) or 32 calibers twist rates,
1768-414: A single diameter. Rifled bores may be described by the bore diameter (the diameter across the lands or high points in the rifling), or by groove diameter (the diameter across the grooves or low points in the rifling). Differences in naming conventions for cartridges can cause confusion; for example, the projectiles of the .303 British are actually slightly larger in diameter than the projectiles of
1872-469: A single person, which was later used effectively as a shock weapon in the siege of De'an in 1132. In the 13th century, fire lance barrels were replaced with metal tubes and transformed into the metal-barreled hand cannon . The technology gradually spread throughout Eurasia during the 14th century. Older firearms typically used black powder as a propellant , but modern firearms use smokeless powder or other explosive propellants. Most modern firearms (with
1976-469: A single soldier, though some are crew-served weapons that require a dedicated crew of soldiers to operate, usually between two and six soldiers depending on the machine gun's operation and the crew members' roles (ammunition bearers, spotters, etc.). Machine guns can be divided into three categories: light machine guns , individual-served machine guns of an intermediate cartridge that are usually magazine-fed; medium machine guns , belt-fed machine guns of
2080-417: A throwback to the earliest types of rifling, has become popular, especially in handguns . Polygonal barrels tend to have longer service lives because the reduction of the sharp edges of the land (the grooves are the spaces that are cut out, and the resulting ridges are called lands) reduces erosion of the barrel. Supporters of polygonal rifling also claim higher velocities and greater accuracy. Polygonal rifling
2184-410: A time by the user, rather than automatically. Manual action firearms can be divided into two basic categories: single-shot firearms that can only be fired once per barrel before it must be reloaded or charged via an external mechanism or series of steps; and repeating firearms that can be fired multiple times per barrel, but can only be fired once with each subsequent pull of the trigger or ignite, and
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#17328561354802288-673: A very high spin rate which can cause projectile jacket ruptures causing high velocity spin stabilized projectiles to disintegrate in flight. Projectiles made out of mono metals cannot practically achieve flight and spin velocities such that they disintegrate in flight due to their spin rate. Smokeless powder can produce muzzle velocities of approximately 1,600 m/s (5,200 ft/s) for spin stabilized projectiles and more advanced propellants used in smoothbore tank guns can produce muzzle velocities of approximately 1,800 m/s (5,900 ft/s). A higher twist than needed can also cause more subtle problems with accuracy: Any inconsistency within
2392-472: Is 150 (use 180 for muzzle velocities higher than 2,800 f/s); D {\displaystyle D} is the bullet's diameter in inches; L {\displaystyle L} is the bullet's length in inches; and S G {\displaystyle \mathrm {SG} } is the bullet's specific gravity (10.9 for lead-core bullets, which cancels out the second half of the equation). The original value of C {\displaystyle C}
2496-485: Is a big draw to the city of Lithgow. Alongside the weapons listed below, the factory also produced bayonets, components, barrels, and magazines as well as repairing, modifying, and rechambering weapons. A broad variety of weapons complemented the factory's military production, but also civilian products such as aircraft parts, golf heads, and tractor components, amongst other things. Discontinued firearms: Current production firearms: Small arms A firearm
2600-551: Is a long gun that has a predominantly smoothbore barrel—meaning it lacks rifling—designed to fire a number of shot pellets in each discharge. These shot pellet sizes commonly range between 2 mm #9 birdshot and 8.4 mm #00 (double-aught) buckshot, and produce a cluster of impact points with considerably less range and accuracy, since shot spreads during flight. Shotguns are also capable of firing single solid projectiles called slugs , or specialty (often " less lethal ") munitions such as bean bags or tear gas to function as
2704-616: Is a magazine-fed carbine chambered in a small-caliber handgun cartridge (such as 9×19mm Parabellum , .45 ACP , .22 Long Rifle , and .40 S&W ). They cannot be considered machine guns due to their small-caliber, hence the prefix " sub- " to differentiate them from proper machine guns. Submachine guns are commonly associated with high rates of fire, automatic fire capabilities, and low recoil, though many submachine guns differentiate from this in various ways, such as having fairly low rates of fire or including burst and semi-automatic modes available through selective fire. Most submachine guns are
2808-417: Is any firearm with a notably long barrel, typically a length of 10 to 30 inches (250 to 760 mm) (there are restrictions on minimum barrel length in many jurisdictions; maximum barrel length is usually a matter of practicality). Unlike a handgun, long guns are designed to be held and fired with both hands, while braced against either the hip or the shoulder for better stability. The receiver and trigger group
2912-408: Is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries (see legal definitions ). The first firearms originated in 10th-century China , when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears to make the portable fire lance , operable by
3016-604: Is currently seen on pistols from CZ , Heckler & Koch , Glock , Tanfoglio , and the Kahr Arms ( P series only), as well as the Desert Eagle . For field artillery pieces, the extended range, full bore (ERFB) concept developed in early 1970s by Dennis Hyatt Jenkins and Luis Palacio of Gerald Bull 's Space Research Corporation for the GC-45 howitzer replaces the bourrelet with small nubs, which both tightly fit into lands of
3120-404: Is in fact fairly common. Since a reduction in twist rate is very detrimental to accuracy, gunsmiths who are machining a new barrel from a rifled blank will often measure the twist carefully so they may put the faster rate, no matter how minute the difference is, at the muzzle end. The original firearms were loaded from the muzzle by forcing a ball from the muzzle to the chamber. Whether using
3224-540: Is most suitable as a light or medium machine gun but fares well as a heavy machine gun. A closely related concept is the squad automatic weapon , a portable light machine gun or even a modified rifle that is designed and fielded to provide a squad with rapid direct fire . Examples of machine guns include the Maxim gun , M2 Browning , Bren light machine gun , MG 42 , PK machine gun , FN MAG , M249 light machine gun , RPK , IWI Negev , and M134 Minigun . A submachine gun
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3328-467: Is mounted into a stock made of wood, plastic, metal, or composite material, which has sections 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-19th century, were generally smoothbore firearms that fired one or more ball shot, called muskets or arquebuses depending on caliber and firing mechanism. Since
3432-415: Is not capable of imparting a spin to a projectile, so a rifled barrel has a non-circular cross-section. Typically the rifled barrel contains one or more grooves that run down its length, giving it a cross-section resembling an internal gear , though it can also take the shape of a polygon , usually with rounded corners. Since the barrel is not circular in cross-section, it cannot be accurately described with
3536-448: Is removed from the chamber. The specified diameter of the throat may be somewhat greater than groove diameter, and may be enlarged by use if hot powder gas melts the interior barrel surface when the rifle is fired. Freebore is a groove-diameter length of smoothbore barrel without lands forward of the throat. Freebore allows the bullet to transition from static friction to sliding friction and gain linear momentum prior to encountering
3640-502: Is the twist rate expressed in bore diameters; L {\displaystyle L} is the twist length required to complete one full projectile revolution (in mm or in); and D bore {\displaystyle D_{\text{bore}}} is the bore diameter (diameter of the lands, in mm or in). The twist travel L {\displaystyle L} and the bore diameter D bore {\displaystyle D_{\text{bore}}} must be expressed in
3744-457: Is the twist rate. For example, an M4 Carbine with a twist rate of 1 in 7 inches (177.8 mm) and a muzzle velocity of 3,050 feet per second (930 m/s) will give the bullet a spin of 930 m/s / 0.1778 m = 5.2 kHz (314,000 rpm). Excessive rotational speed can exceed the bullet's designed limits and the resulting centrifugal force can cause the bullet to disintegrate radially during flight. A barrel of circular bore cross-section
3848-411: Is usually seen as "keyholing", where bullets leave elongated holes in the target as they strike at an angle. Once the bullet starts to yaw, any hope of accuracy is lost, as the bullet will begin to veer off in random directions as it precesses . Conversely, too high a rate of twist can also cause problems. The excessive twist can cause accelerated barrel wear, and coupled with high velocities also induce
3952-421: Is usually sized slightly larger than the projectile, so the loaded cartridge can be inserted and removed easily, but the throat should be as close as practical to the groove diameter of the barrel. Upon firing, the projectile expands under the pressure from the chamber, and obturates to fit the throat. The bullet then travels down the throat and engages the rifling, where it is engraved, and begins to spin. Engraving
4056-446: The .308 Winchester , because the ".303" refers to the bore diameter in inches (bullet is .312), while the ".308" refers to the bullet diameter in inches (7.92 mm and 7.82 mm, respectively). Despite differences in form, the common goal of rifling is to deliver the projectile accurately to the target. In addition to imparting the spin to the bullet, the barrel must hold the projectile securely and concentrically as it travels down
4160-460: The 20 mm M61 Vulcan Gatling gun used in some current fighter jets and the larger 30 mm GAU-8 Avenger Gatling gun used in the A10 Thunderbolt II close air support jet. In these applications it allows lighter construction of the barrels by decreasing chamber pressures through the use of low initial twist rates but ensuring the projectiles have sufficient stability once they leave
4264-520: The AK-74 and AKS-74U . However, some carbines, such as the M1 carbine , are not a variant of any existing design and are their own firearm model. Carbines are regardless very similar to rifles and often have the same actions (single-shot, lever-action, bolt-action, semi-automatic, automatic, etc.). This similarity has given carbines the alternate name of short barreled rifle (SBR), though this more accurately describes
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4368-712: The Australian military . As a separate entity, not owned or run by the current owners of the factory, the volunteer-run Lithgow Small Arms Factory Museum is located at the front of the disused section of site and has a large collection of military and civilian firearms manufactured at the factory and elsewhere. In 2019, the museum was placed on the UNESCO Australian Memory of the World Register which lists influential collections and documents considered key to Australia's history . The museum sees 9,000 annual visitors and
4472-587: The FG 42 , Gewehr 43 , FN FAL , Howa Type 64 , and Desert Tech MDR . A sniper rifle is, per widespread definition, a high-powered precision rifle, often bolt-action or semi-automatic, with an effective range farther than that of a standard rifle. Though any rifle in a sniper configuration (usually with a telescopic sight and bipod ) can be considered a sniper rifle, most sniper rifles are purpose-built for their applications, or are variants of existing rifles that have been modified to function as sniper rifles, such as
4576-589: The Glock , Browning Hi-Power , M1911 pistol , Makarov pistol , Walther PP , Luger pistol , Mauser C96 , and Beretta 92 . Examples of revolvers include the Colt Single Action Army , Smith & Wesson Model 10 , Colt Official Police , Colt Python , New Nambu M60 , and Mateba Autorevolver . Examples of derringers include the Remington Model 95 , FP-45 Liberator , and COP .357 Derringer . A long gun
4680-500: The M26 Modular Accessory Shotgun System . Shotguns are still popular with civilians for the suitability of their shot spread in hunting, clay pigeon shooting , and home defense. Double-barreled shotguns are break-action shotguns with two parallel barrels (horizontal side-by-side or vertical over-and-under), allowing two single shots that can be loaded and fired in quick succession. Examples of shotguns include
4784-509: The MP 18 , MP 40 , Thompson submachine gun , M3 submachine gun , Uzi , Heckler & Koch MP5 , Spectre M4 , Steyr TMP , Heckler & Koch UMP , PP-2000 , KRISS Vector , and SIG MPX . A personal defense weapon is, in simplest terms, a submachine gun that is designed to fire ammunition with ballistic performance that is similar to (but not actually a type of) rifle cartridges, often called "sub-intermediate" cartridges. In this way, it combines
4888-649: The Mauser Tankgewehr M1918 , Boys anti-tank rifle , PTRS-41 , Barrett M82 , Gepárd anti-materiel rifle , and McMillan TAC-50 . Examples of designated marksman rifles include the SVD , SR-25 , Dragunov SVU , Marine Scout Sniper Rifle , Mk 14 Enhanced Battle Rifle , and M110 Semi-Automatic Sniper System . An automatic rifle is a magazine-fed rifle that is capable of automatic fire. They include most assault rifles and battle rifles, but originated as their own category of rifles capable of automatic fire, as opposed to
4992-784: The National Firearms Act and Firearm Owners Protection Act define a "machine gun" in 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 American civilian parlance, covering all automatic firearms. In most jurisdictions, automatic rifles, as well as automatic firearms in general, are prohibited from civilian purchase or are at least heavily restricted; in
5096-638: The Springfield Armory (United States), the Royal Small Arms Factory (United Kingdom), Mauser (Germany), Steyr-Daimler-Puch (Austria), and Rock Island Armory under Armscor (Philippines). As of 2018 the Small Arms Survey reported that there were over one billion firearms distributed globally, of which 857 million (about 85 percent) were in civilian hands. U.S. civilians alone account for 393 million (about 46 percent) of
5200-464: The StG 44 produced by Nazi Germany during World War II , assault rifles have since become extremely popular among militaries and other armed groups due to their universal versatility, and they have made up the vast majority of standard-issue military service rifles since the mid-20th century. Various configurations of assault rifle exist, such as the bullpup , in which the firing grip is located in front of
5304-539: The Type 97 sniper rifle , which was essentially a standard Type 38 rifle that was modified to be lighter and come with a telescopic sight. Related developments are anti-materiel rifles , large-caliber rifles designed to destroy enemy materiel such as vehicles, supplies, or hardware; anti-tank rifles , anti-materiel rifles that were designed specifically to combat early armoured fighting vehicles , but are now largely obsolete due to advances in vehicle armour ; scout rifles ,
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#17328561354805408-520: The Winchester Model 1892 , Rifle No. 5 Mk I , SKS , M1 carbine , Ruger Mini-14 , M4 carbine , and Kel-Tec SUB-2000 . An assault rifle is commonly defined as a selective-fire rifle chambered in an intermediate cartridge (such as 5.56×45mm NATO , 7.62×39mm , 5.45×39mm , and .300 AAC Blackout ) and fed with a detachable magazine . Assault rifles are also usually smaller than full-sized rifles such as battle rifles . Originating with
5512-425: The Winchester Model 1897 , Browning Auto-5 , Ithaca 37 , Remington Model 870 , Mossberg 500 , Benelli M4 , Franchi SPAS-12 , Atchisson AA-12 , and Knight's Armament Company Masterkey . A carbine is a long gun, usually a rifle, that has had its barrel shortened from its original length or is of a certain size smaller than standard rifles, but is still large enough to be considered a long gun. How considerable
5616-633: The breech instead of behind it. Examples of assault rifles include the Kalashnikov rifles of Soviet and Russian origin (such as the AK-47 , AKM , and AK-74 ), as well as the American M4 carbine and M16 rifle . A battle rifle is commonly defined as a semi-automatic or selective-fire rifle that is larger or longer than an assault rifle and is chambered in a "full-power" cartridge (e.g. 7.62×51mm NATO , 7.92×57mm Mauser , 7.62×54mmR ). The term originated as
5720-450: The firing pin mechanism, expelling the old cartridge and loading a new one. Rifling Rifling is measured in twist rate , the distance the rifling takes to complete one full revolution, expressed as a ratio with 1 as its base (e.g., 1:10 inches (25.4 cm)). A shorter distance/lower ratio indicates a faster twist, generating a higher spin rate (and greater projectile stability). The combination of length, weight, and shape of
5824-518: The 16th century, it had to be engraved by hand and consequently did not become commonplace until the mid-19th century. Due to the laborious and expensive manufacturing process involved, early rifled firearms were primarily used by wealthy recreational hunters, who did not need to fire their weapons many times in rapid succession and appreciated the increased accuracy. Rifled firearms were not popular with military users since they were difficult to clean, and loading projectiles presented numerous challenges. If
5928-865: The 19th and 20th centuries, various types of long guns have been created for different purposes. A rifle is a long gun that has riflings (spiral grooves) machined into the bore (inner) surface of its barrel, imparting a gyroscopically stabilizing spin to the bullets that it fires. A descendant of the musket, rifles produce a single point of impact with each firing with a long range and high accuracy. For this reason, as well as for their ubiquity, rifles are very popular among militaries as service rifles , police as accurate long-range alternatives to their traditional shotgun long guns, and civilians for hunting , shooting sports , and self-defense . Many types of rifles exist owing to their wide adoption and versatility, ranging from mere barrel length differences as in short-barreled rifles and carbines , to classifications per
6032-426: The 20th century, but have since been superseded in most combat roles by rifles, carbines, and personal defense weapons due to their low effective range and poor penetration against most body armor developed since the late 20th century. However, they remain popular among special forces and police for their effectiveness in close-quarters and low likelihood to overpenetrate targets. Examples of submachine guns include
6136-550: The Australian military during World War I . During World War II , production expanded to include Vickers machine guns , Bren guns and, postwar, branched out into sporting goods (including civilian firearms and golf clubs ), tools, sewing machines , (from the mid-1950s) the F1 submachine gun , L1A1 SLR , KAL1 general purpose infantry rifle prototypes , general purpose machine guns , and similar products. The Lithgow Small Arms Factory
6240-455: The German PzH 2000 . ERFB may be combined with base bleed . A gain-twist or progressive rifling begins with a slow twist rate that gradually increases down the bore, resulting in very little initial change in the projectile's angular momentum during the first few inches of bullet travel after it enters the throat . This enables the bullet to remain essentially undisturbed and trued to
6344-479: The U.S. for instance, most automatic rifles are Title II weapons that require certain licenses and are greatly regulated. Examples of automatic rifles include the Cei-Rigotti , Lewis gun , Fedorov Avtomat , and M1918 Browning automatic rifle . A machine gun is a fully-automatic firearm, chambered in intermediate or full-power rifle cartridges, designed to provide sustained automatic direct fire as opposed to
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#17328561354806448-418: The ball seated on the charge of black powder , and kept the ball concentric to the bore. In rifled barrels, the patch also provided a means to transfer the spin from the rifling to the bullet, as the patch is engraved rather than the ball. Until the advent of the hollow-based Minié ball , which expands and obturates upon firing to seal the bore and engage the rifling, the patch provided the best means of getting
6552-479: The barrel should have a twist rate sufficient to spin stabilize any bullet that it would reasonably be expected to fire, but not significantly more. Large diameter bullets provide more stability, as the larger radius provides more gyroscopic inertia , while long bullets are harder to stabilize, as they tend to be very backheavy and the aerodynamic pressures have a longer arm ("lever") to act on. The slowest twist rates are found in muzzle-loading firearms meant to fire
6656-490: The barrel's twist rate . The general definition of the spin S {\displaystyle S} of an object rotating around a single axis can be written as: S = υ C {\displaystyle S={\frac {\upsilon }{C}}} where υ {\displaystyle \upsilon } is the linear velocity of a point in the rotating object (in units of distance/time) and C {\displaystyle C} refers to
6760-462: The barrel. Guns capable of firing these projectiles have achieved significant increases in range, but this is compensated with a significantly (3–4 times) decreased accuracy, due to which they were not adopted by NATO militaries. Unlike a shell narrower than the gun's bore with a sabot , ERFB shells use the full bore, permitting a larger payload. Examples include the South African G5 and
6864-404: The barrel. This requires that the rifling meet a number of tasks: Rifling may not begin immediately forward of the chamber. There may be an unrifled throat ahead of the chamber so a cartridge may be chambered without pushing the bullet into the rifling. This reduces the force required to load a cartridge into the chamber, and prevents leaving a bullet stuck in the rifling when an unfired cartridge
6968-839: The bolt-action and semi-automatic rifles commonly issued to infantry at the time of their invention. They usually have smaller magazine capacities than machine guns ; the French Chauchat had a 20-round box magazine, while the Hotchkiss Mle 1914 machine gun , the French Army 's standard machine gun at the time, was fed by a 250-round ammunition belt . Though automatic rifles are sometimes considered to be their own category, they are also occasionally considered to be other types of firearms that postdated their invention, usually as light machine guns . Automatic rifles are sometimes confused with machine guns or vice versa, or are defined as such by law;
7072-468: The bullet was of sufficient diameter to take up the rifling, a large mallet was required to force it down the bore. If, on the other hand, it was of reduced diameter to assist in its insertion, the bullet would not fully engage the rifling and accuracy was reduced. The first practical military weapons using rifling with black powder were breech loaders such as the Queen Anne pistol . For best performance,
7176-418: The bullet, such as a void that causes an unequal distribution of mass, may be magnified by the spin. Undersized bullets also have problems, as they may not enter the rifling exactly concentric and coaxial to the bore, and excess twist will exacerbate the accuracy problems this causes. A bullet fired from a rifled barrel can spin at over 300,000 rpm (5 kHz ), depending on the bullet's muzzle velocity and
7280-404: The case mouth. After engaging the rifling at the throat, the bullet is progressively subjected to accelerated angular momentum as it is propelled down the barrel. The theoretical advantage is that by gradually increasing the spin rate, torque is imparted along a much longer bore length, allowing thermomechanical stress to be spread over a larger area rather than being focused predominantly at
7384-456: The circumference of the circle that this measuring point performs around the axis of rotation. A bullet that matches the rifling of the firing barrel will exit that barrel with a spin: S = υ 0 L {\displaystyle S={\frac {\upsilon _{0}}{L}}} where υ 0 {\displaystyle \upsilon _{0}} is the muzzle velocity and L {\displaystyle L}
7488-495: The civilian market, albeit often with longer barrels. Examples of personal defense weapons include the FN P90 , Heckler & Koch MP7 , AAC Honey Badger , and ST Kinetics CPW . Types aside, firearms are also categorized by their "action", which describes their loading, firing, and unloading cycle. Manual action or manual operation is essentially any type of firearm action that is loaded, and usually also fired, one cartridge at
7592-699: The design's primary intended use (e.g. hunting rifle), or to the commonly accepted name for a particular variation (e.g. Gatling gun ). Shooters aim firearms at their targets with hand-eye coordination , using either iron sights or optical sights . The accurate range of pistols generally does not exceed 100 metres (110 yd; 330 ft), while most rifles are accurate to 500 metres (550 yd; 1,600 ft) using iron sights, or to longer ranges whilst using optical sights. Purpose-built sniper rifles and anti-materiel rifles are accurate to ranges of more than 2,000 metres (2,200 yd). (Firearm rounds may be dangerous or lethal well beyond their accurate range;
7696-507: The difference is between a rifle and a carbine varies; for example, the standard Heckler & Koch G36 's barrel has a length of 480 mm (18.9 in), the G36K carbine variant's barrel is 318 mm (12.5 in), and the G36C compact variant's barrel is 228 mm (9.0 in). Some carbines are also redesigned compared to their rifle counterparts, such as the aforementioned G36/G36K and G36C, or
7800-447: The end of the 15th century only used straight grooves, and it was not until he received help from Kotter that a working spiral-grooved firearm was made. There may have been attempts even earlier than this, as the main inspiration of rifled firearms came from archers and crossbowmen who realized that their projectiles flew far faster and more accurately when they imparted rotation through twisted fletchings. Though true rifling dates from
7904-423: The firearm's action must be reloaded or charged via an internal mechanism between trigger pulls. Types of manual actions include lever action, bolt action, and pump action. Lever action is a repeating action that is operated by using a cocking handle (the "lever") located around the trigger guard area (often incorporating it) that is pulled down then back up to move the bolt via internal linkages and cock
8008-403: The global total of small arms. A handgun is, as defined generally and in many gun laws , a firearm that can be used with a single hand. They are the smallest of all firearms, and are common as sidearms , concealed carry weapons, or as backup weapons for self-defense . Handguns can be categorized into two broad types: pistols , which have a single fixed firing chamber machined into
8112-457: The high automatic rate of fire, reliable low recoil, and lightweight compact maneuverability of submachine guns with the versatility, penetration, and effective range of rifles, effectively making them an "in-between" of submachine guns and carbines. Personal defense weapons were developed to provide rear and "second-line" personnel not otherwise armed with high-caliber firearms (vehicle and weapon crews, engineers, logistical personnel, etc.) with
8216-430: The inventor of barrel rifling is not yet definitely known. Straight grooving had been applied to small arms since at least 1480, originally intended as "soot grooves" to collect gunpowder residue . Some of the earliest recorded European attempts of spiral-grooved musket barrels were of Gaspard Kollner , a gunsmith of Vienna in 1498 and Augustus Kotter of Nuremberg in 1520. Some scholars allege that Kollner's works at
8320-836: The minimum distance for safety is much greater than the specified range for accuracy.) A firearm is a barreled ranged weapon that inflicts damage on targets by launching one or more projectiles driven by rapidly expanding high-pressure gas produced by exothermic combustion ( deflagration ) of a chemical propellant , historically black powder , now smokeless powder . In the military, firearms are categorized into heavy and light weapons regarding their portability by infantry . Light firearms are those that can be readily carried by individual foot soldier , though they might still require more than one individual ( crew-served ) to achieve optimal operational capacity. Heavy firearms are those that are too large and heavy to be transported on foot, or too unstable against recoil , and thus require
8424-512: The musket; both having single-shot , break-action , bolt-action , lever-action , pump-action , semi-automatic , and automatic variants; and both being popular with militaries, police, and civilians for largely the same reasons. However, unlike rifles, shotguns are less favored in combat roles due to their low accuracy and limited effectiveness in modern warfare , with combat shotguns often only used for breaching or close-quarters combat and sometimes limited to underbarrel attachments such as
8528-399: The notable exception of smoothbore shotguns ) have rifled barrels to impart spin to the projectile for improved flight stability. Modern firearms can be described by their caliber (i.e. bore diameter). For pistols and rifles this is given in millimeters or inches (e.g. 7.62mm or .308 in.); in the case of shotguns, gauge or bore (e.g. 12 ga. or .410 bore.). They are also described by
8632-411: The projectile requires a significant amount of force, and in some firearms there is a significant amount of freebore, which helps keep chamber pressures low by allowing the propellant gases to expand before being required to engrave the projectile. Minimizing freebore improves accuracy by decreasing the chance that a projectile will distort before entering the rifling. When the projectile is swaged into
8736-407: The projectile to engage the rifling. In breech-loading firearms , the task of seating the projectile into the rifling is handled by the throat of the chamber . Next is the freebore , which is the portion of the throat down which the projectile travels before the rifling starts. The last section of the throat is the throat angle , where the throat transitions into the rifled barrel. The throat
8840-734: The rear of the barrel, and are often loaded using magazines of varying capacities; revolvers , which have a number of firing chambers or "charge holes" in a revolving cylinder , each one loaded with a single cartridge or charge; and derringers , broadly defined as any handgun that is not a traditional pistol nor a revolver. There are various types of the aforementioned handguns designed for different mechanisms or purposes, such as single-shot , manual repeating , semi-automatic , or automatic pistols; single-action , double-action , or double-action/single-action revolvers; and small, compact handguns for concealed carry such as pocket pistols and " Saturday night specials ". Examples of pistols include
8944-487: The required depth was obtained. The process was finished off by casting a slug of molten lead into the barrel, withdrawing it and using it with a paste of emery and oil to smooth the bore. Most rifling is created by either: The grooves are the spaces that are cut out, and the resulting ridges are called lands . These lands and grooves can vary in number, depth, shape, direction of twist (right or left), and twist rate. The spin imparted by rifling significantly improves
9048-413: The resistance of increasing rotational momentum. Freebore may allow more effective use of propellants by reducing the initial pressure peak during the minimum volume phase of internal ballistics before the bullet starts moving down the barrel. Barrels with freebore length exceeding the rifled length have been known by a variety of trade names including paradox . An early method of introducing rifling to
9152-523: The rifle's function and purpose as in semi-automatic rifles , automatic rifles and sniper rifles , to differences in the rifle's action as in single-shot , break-action , bolt-action , and lever-action rifles. Examples of rifles of various types include the Henry rifle , Winchester rifle , Lee–Enfield , Gewehr 98 , M1 Garand , MAS-36 rifle , AKM , Ruger 10/22 , Heckler & Koch G3 , Remington Model 700 , and Heckler & Koch HK417 . A shotgun
9256-529: The rifled barrel. This method does not give an easy or straightforward understanding of whether a twist rate is relatively slow or fast when bores of different diameters are compared. The second method describes the 'rifled travel' required to complete one full projectile revolution in calibers or bore diameters: twist = L D bore , {\displaystyle {\text{twist}}={\frac {L}{D_{\text{bore}}}},} where twist {\displaystyle {\text{twist}}}
9360-512: The rifling, it takes on a mirror image of the rifling, as the lands push into the projectile in a process called engraving . Engraving takes on not only the major features of the bore, such as the lands and grooves, but also minor features, like scratches and tool marks. The relationship between the bore characteristics and the engraving on the projectile are often used in forensic ballistics . The grooves most commonly used in modern rifling have fairly sharp edges. More recently, polygonal rifling ,
9464-469: The same as used for the M16 rifle. Rifles, which generally fire longer, smaller diameter bullets, will in general have higher twist rates than handguns, which fire shorter, larger diameter bullets. There are three methods in use to describe the twist rate: The, traditionally speaking, most common method expresses the twist rate in terms of the 'travel' (length) required to complete one full projectile revolution in
9568-510: The same purposes. However, some prefer battle rifles for their more powerful cartridge, despite the added recoil. Some designated marksman rifles are configured from battle rifles, such as the Mk 14 Enhanced Battle Rifle and United States Marine Corps Designated Marksman Rifle , both essentially heavily modified and modernized variants of the M14 rifle . Examples of rifles considered to be battle rifles include
9672-596: The semi-automatic or burst fire of standard rifles. They are commonly associated with being belt-fed , though many machine guns are also fed by box, drum, pan, or hopper magazines. They generally have a high rate of fire and a large ammunition capacity, and are often used for suppressive fire to support infantry advances or defend positions from enemy assaults. Owing to their versatility and firepower, they are also commonly installed on military vehicles and military aircraft , either as main or ancillary weapons . Many machine guns are individual-served and can be operated by
9776-405: The sides of the barrel when fired and the final destination after leaving the muzzle was less predictable. This was countered when accuracy was more important, for example when hunting, by using a tighter-fitting combination of a closer-to-bore-sized ball and a patch. The accuracy was improved, but still not reliable for precision shooting over long distances. Like the invention of gunpowder itself,
9880-586: The size of carbines and short-barreled rifles, and use similar configurations. Many are designed to take as little space as possible for use in close-quarters or for easy storage in vehicles and cases. Some submachine guns are designed and configured similar to pistols even down to size, and are thus occasionally classed as machine pistols , even if they are not actually a handgun (i.e. designed to require two hands to use). Submachine guns are considered ideal for close-quarters combat and are cheap to mass-produce. They were very common in military service through much of
9984-404: The stability of the projectile, improving both range and accuracy. Typically rifling is a constant rate down the barrel, usually measured by the length of travel required to produce a single turn. Occasionally firearms are encountered with a gain twist , where the rate of spin increases from chamber to muzzle. While intentional gain twists are rare, due to manufacturing variance, a slight gain twist
10088-560: The support of a weapons platform (e.g. a fixed mount , wheeled carriage , vehicle , aircraft or water vessel ) to be tactically mobile or useful. The subset of light firearms that only use kinetic projectiles and are compact enough to be operated to full capacity by a single infantryman (individual-served) are also referred to as small arms . Such firearms include handguns such as pistols , revolvers , and derringers ; and long guns such as rifles (and their subtypes), shotguns , submachine guns , and machine guns . Among
10192-480: The throat, which typically wears out much faster than other parts of the barrel. Gain-twist rifling was used prior to and during the American Civil War (1861–65). Colt Army and Navy revolvers both employed gain-twist rifling. Gain-twist rifling, however, is more difficult to produce than uniform rifling, and therefore is more expensive. The military has used gain-twist rifling in a variety of weapons such as
10296-449: The twist rate from breech to muzzle is called a gain or progressive twist; a rate which decreases down the length of a barrel is undesirable because it cannot reliably stabilize the projectile as it travels down the bore. An extremely long projectile, such as a flechette , requires impractically high twist rates to stabilize; it is often stabilized aerodynamically instead. An aerodynamically stabilized projectile can be fired from
10400-456: The type of action employed (e.g. muzzleloader , breechloader , lever , bolt , pump , revolver , semi-automatic , fully automatic , etc.), together with the usual means of deportment (i.e. hand-held or mechanical mounting). Further classification may make reference to the type of barrel used (i.e. rifled ) and to the barrel length (e.g. 24 inches), to the firing mechanism (e.g. matchlock , wheellock , flintlock , or percussion lock ), to
10504-414: The world's arms manufacturers , the top firearms manufacturers are Browning , Remington , Colt , Ruger , Smith & Wesson , Savage , Mossberg (United States), Heckler & Koch , SIG Sauer , Walther (Germany), ČZUB (Czech Republic), Glock , Steyr Arms (Austria), FN Herstal (Belgium), Beretta (Italy), Norinco (China), Rostec , and Kalashnikov (Russia). Former top producers included
10608-485: The worldwide total of civilian-held firearms. This amounts to "120.5 firearms for every 100 residents". The world's armed forces control about 133 million (about 13 percent) of the global total of small arms, of which over 43 percent belong to two countries: the Russian Federation (30.3 million) and China (27.5 million). Law enforcement agencies control about 23 million (about 2 percent) of
10712-434: Was 150, which yields a twist rate in inches per turn, when given the diameter D {\displaystyle D} and the length L {\displaystyle L} of the bullet in inches. This works to velocities of about 840 m/s (2800 ft/s); above those velocities, a C {\displaystyle C} of 180 should be used. For instance, with a velocity of 600 m/s (2000 ft/s),
10816-551: Was known to produce their single shot models 1A and 1B as well as their Model 12 repeater under the Slazenger brand during the 1960s. The factory was first "corporatised" as Australian Defence Industries by the Hawke government , then later sold in 2006. ADI Lithgow is now owned by Thales Australia and continues to manufacture the F88 Austeyr rifle and F89 Minimi currently used by
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