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79-538: Austin Cartridge Company was an Austin Powder Company subsidiary manufacturing cartridge ammunition for small arms . The company made shotgun shells and rimfire cartridges from 1895 until purchased by Western Cartridge Company in 1907. Austin Powder Company was founded in 1833 by brothers Daniel, Alvin, Lorenzo, Henry, and Linus Austin of Wilmington, Vermont . After exploring the market for gunpowder on

158-501: A shot , contains explosives or other fillings, in use since the 19th century. Artillery shells are ammunition that is designed to be fired from artillery which has an effect over long distances, usually indirectly (i.e., out of sight of the target). There are many different types of artillery ammunition, but they are usually high-explosive and designed to shatter into fragments on impact to maximize damage. The fuze used on an artillery shell can alter how it explodes or behaves so it has

237-509: A UCC headstamp appeared on the rimfire cartridges. These were the first .22 rimfire cartridges manufactured by Western Cartridge Company. Austin Cartridge Company was sold to Western Cartridge Company in 1907 as Austin Powder Company reorganized to focus on production of blasting explosives . Western Cartridge Company used the Maltese cross trade mark until replacing it with a diamond trade mark during World War I . Ammunition Ammunition

316-419: 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 ,

395-404: A corresponding modification has occurred in the method of supplying ammunition in the quantity required. As soon as projectiles were required (such as javelins and arrows), there needed to be a method of replenishment. When non-specialized, interchangeable or recoverable ammunition was used (e.g., arrows), it was possible to pick up spent arrows (both friendly and enemy) and reuse them. However, with

474-588: 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

553-409: A modern soldier is an assault rifle , which, like other small arms, uses cartridge ammunition in a size specific to the weapon. Ammunition is carried on the person in box magazines specific to the weapon, ammunition boxes, pouches or bandoliers. The amount of ammunition carried is dependent on the strength of the soldier, the expected action required, and the ability of ammunition to move forward through

632-422: A more specialized effect. Common types of artillery ammunition include high explosive, smoke, illumination, and practice rounds. Some artillery rounds are designed as cluster munitions . Artillery ammunition will almost always include a projectile (the only exception being demonstration or blank rounds), fuze and propellant of some form. When a cartridge case is not used, there will be some other method of containing

711-469: 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

790-660: 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}

869-414: 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

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948-519: A significant impact on anti-tank ammunition design, now common in both tank-fired ammunition and in anti-tank missiles, including anti-tank guided missiles . Naval weapons were originally the same as many land-based weapons, but the ammunition was designed for specific use, such as a solid shot designed to hole an enemy ship and chain-shot to cut rigging and sails. Modern naval engagements have occurred over far longer distances than historic battles, so as ship armor has increased in strength and thickness,

1027-414: 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

1106-401: A specialized effect on a target, such as armor-piercing shells and tracer ammunition , used only in certain circumstances. Ammunition is commonly labeled or colored in a specific manner to assist in its identification and to prevent the wrong ammunition types from being used accidentally or inappropriately. The term ammunition can be traced back to the mid-17th century. The word comes from

1185-417: 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

1264-420: 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, 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

1343-673: 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

1422-422: 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 the twist rate from breech to muzzle is called a gain or progressive twist; a rate which decreases down

1501-425: A warship is referred to as the "ship's magazine". On a smaller scale, magazine is also the name given to the ammunition storage and feeding device of a repeating firearm. Gunpowder must be stored in a dry place (stable room temperature) to keep it usable, as long as for 10 years. It is also recommended to avoid hot places, because friction or heat might ignite a spark and cause an explosion. The standard weapon of

1580-472: 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}

1659-408: Is activated by the fuze, which causes the ammunition effect (e.g., the exploding of an artillery round). The cartridge is the container that holds the projectile and propellant. Not all ammunition types have a cartridge case. In its place, a wide range of materials can be used to contain the explosives and parts. With some large weapons, the ammunition components are stored separately until loaded into

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1738-604: 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

1817-404: 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

1896-415: 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

1975-413: Is packaged with each round of ammunition. In recent years, compressed gas, magnetic energy and electrical energy have been used as propellants. Until the 20th-century, gunpowder was the most common propellant in ammunition. However, it has since been replaced by a wide range of fast-burning compounds that are more reliable and efficient. The propellant charge is distinct from the projectile charge which

2054-448: 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

2133-626: Is the firearm cartridge , which includes all components required to deliver the weapon effect in a single package. Until the 20th century, black powder was the most common propellant used but has now been replaced in nearly all cases by modern compounds. Ammunition comes in a great range of sizes and types and is often designed to work only in specific weapons systems. However, there are internationally recognized standards for certain ammunition types (e.g., 5.56×45mm NATO ) that enable their use across different weapons and by different users. There are also specific types of ammunition that are designed to have

2212-451: Is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs , missiles , grenades , land mines ) and the component parts of other weapons that create the effect on a target (e.g., bullets and warheads ). The purpose of ammunition is to project a force against a selected target to have an effect (usually, but not always, lethal). An example of ammunition

2291-453: Is the second-largest annual use of lead in the US, accounting for over 60,000 metric tons consumed in 2012. Lead bullets that miss their target or remain in a carcass or body that was never retrieved can enter environmental systems and become toxic to wildlife. The US military has experimented with replacing lead with copper as a slug in their green bullets which reduces the dangers posed by lead in

2370-502: 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

2449-457: 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

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2528-411: 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

2607-421: 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

2686-446: 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

2765-460: 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

2844-663: 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, 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

2923-488: The detonator of an explosive round or shell. The spelling is different in British English and American English (fuse/fuze respectively) and they are unrelated to a fuse (electrical) . A fuse was earlier used to ignite the propellant (e.g., such as on a firework) until the advent of more reliable systems such as the primer or igniter that is used in most modern ammunition. The fuze of a weapon can be used to alter how

3002-580: The propellant bags, usually a breech-loading weapon; see Breechloader . Tank ammunition was developed in WWI as tanks first appeared on the battlefield. However, as tank-on-tank warfare developed (including the development of anti-tank warfare artillery), more specialized forms of ammunition were developed such as high-explosive anti-tank (HEAT) warheads and armour-piercing discarding sabot (APDS), including armour-piercing fin-stabilized discarding sabot (APFSDS) rounds. The development of shaped charges has had

3081-519: The western frontier , they built and operated a gun powder mill at Old Forge on the Cuyahoga River near Akron, Ohio . Early production was largely used as blasting powder for coal mining but some was sold as sporting rifle powder. In 1884 the company became the exclusive supplier of gunpowder for shotgun shells manufactured by Chamberlain Cartridge Company. Austin Powder Company built the company town of Glenwillow, Ohio in 1892, and established

3160-482: The Austin Cartridge Company there in 1895 manufacturing Crack Shot , Club Sporting , and Champion Ducking shotgun shells. The Union Cap and Chemical Company was formed in 1900 as a joint venture of Austin Cartridge Company and Western Cartridge Company to manufacture blasting caps , primers , and .22 and .32 caliber rimfire cartridges. The Union Cap and Chemical Company trademark was a Maltese cross and

3239-640: The French la munition , for the material used for war. Ammunition and munition are often used interchangeably, although munition now usually refers to the actual weapons system with the ammunition required to operate it. In some languages other than English ammunition is still referred to as munition, such as: Dutch (" munitie "), French (" munitions "), German (" Munition "), Italian (" munizione ") and Portuguese (" munição "). Ammunition design has evolved throughout history as different weapons have been developed and different effects required. Historically, ammunition

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3318-455: 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

3397-618: The advent of explosive or non-recoverable ammunition, this was no longer possible and new supplies of ammunition would be needed. The weight of ammunition required, particularly for artillery shells, can be considerable, causing a need for extra time to replenish supplies. In modern times, there has been an increase in the standardization of many ammunition types between allies (e.g., the NATO Standardization Agreement ) that has allowed for shared ammunition types (e.g., 5.56×45mm NATO). As of 2013, lead-based ammunition production

3476-406: The aerodynamic pressures have a longer arm ("lever") to act on. The slowest twist rates are found in muzzle-loading firearms meant to fire 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

3555-500: The ammunition has cleared the weapon. The propellant is the component of ammunition that is activated inside the weapon and provides the kinetic energy required to move the projectile from the weapon to the target. Before the use of gunpowder, this energy would have been produced mechanically by the weapons system (e.g., a catapult or crossbow); in modern times, it is usually a form of chemical energy that rapidly burns to create kinetic force, and an appropriate amount of chemical propellant

3634-405: The ammunition to defeat it has also changed. Naval ammunition is now designed to reach very high velocities (to improve its armor-piercing abilities) and may have specialized fuzes to defeat specific types of vessels. However, due to the extended ranges at which modern naval combat may occur, guided missiles have largely supplanted guns and shells. With every successive improvement in military arms,

3713-436: The ammunition works. For example, a common artillery shell fuze can be set to "point detonation" (detonation when it hits a target), delay (detonate after it has hit and penetrated a target), time-delay (explode a specified time after firing or impact) and proximity (explode above or next to a target without hitting it, such as for airburst effects or anti-aircraft shells). These allow a single ammunition type to be altered to suit

3792-418: 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

3871-490: 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

3950-462: 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

4029-404: 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

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4108-418: 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

4187-404: 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

4266-456: 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}

4345-616: The damage inflicted by one round. Anti-personnel shells are designed to fragment into many pieces and can affect a large area. Armor-piercing rounds are specially hardened to penetrate armor, while smoke ammunition covers an area with a fog that screens people from view. More generic ammunition (e.g., 5.56×45mm NATO ) can often be altered slightly to give it a more specific effect (e.g., tracer, incendiary), whilst larger explosive rounds can be altered by using different fuzes. The components of ammunition intended for rifles and munitions may be divided into these categories: The term fuze refers to

4424-411: The delivery of explosives. An ammunition dump is a military facility for the storage of live ammunition and explosives that will be distributed and used at a later date. Such a storage facility is extremely hazardous, with the potential for accidents when unloading, packing, and transferring the ammunition. In the event of a fire or explosion, the site and its surrounding area is immediately evacuated and

4503-432: 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 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

4582-405: The environment as a result of artillery. Since 2010, this has eliminated over 2000 tons of lead in waste streams. Hunters are also encouraged to use monolithic bullets , which exclude any lead content. Unexploded ammunition can remain active for a very long time and poses a significant threat to both humans and the environment. Rifling Rifling is measured in twist rate , the distance

4661-427: 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 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

4740-399: The increased accuracy. Rifled firearms were not popular with military users since they were difficult to clean, and loading projectiles presented numerous challenges. If 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

4819-514: 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 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

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4898-424: The logistical chain to replenish the supply. A soldier may also carry a smaller amount of specialized ammunition for heavier weapons such as machine guns and mortars, spreading the burden for squad weapons over many people. Too little ammunition poses a threat to the mission, while too much limits the soldier's mobility also being a threat to the mission. A shell is a payload-carrying projectile which, as opposed to

4977-582: 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 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

5056-435: The potential threat from enemy forces. A magazine is a place where a quantity of ammunition or other explosive material is stored temporarily prior to being used. The term may be used for a facility where large quantities of ammunition are stored, although this would normally be referred to as an ammunition dump. Magazines are typically located in the field for quick access when engaging the enemy. The ammunition storage area on

5135-411: 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

5214-407: 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

5293-487: 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

5372-413: 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

5451-577: 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, 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

5530-472: 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 a projectile determines the twist rate needed to gyroscopically stabilize it: barrels intended for short, large-diameter projectiles such as spherical lead balls require

5609-512: 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 ,

5688-425: The situation it is required for. There are many designs of a fuze, ranging from simple mechanical to complex radar and barometric systems. Fuzes are usually armed by the acceleration force of firing the projectile, and usually arm several meters after clearing the bore of the weapon. This helps to ensure the ammunition is safer to handle when loading into the weapon and reduces the chance of the detonator firing before

5767-404: 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

5846-477: The stored ammunition is left to detonate itself completely with limited attempts at firefighting from a safe distance. In large facilities, there may be a flooding system to automatically extinguish a fire or prevent an explosion. Typically, an ammunition dump will have a large buffer zone surrounding it, to avoid casualties in the event of an accident. There will also be perimeter security measures in place to prevent access by unauthorized personnel and to guard against

5925-480: 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

6004-709: 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 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}}}

6083-414: The weapon system for firing. With small arms, caseless ammunition can reduce the weight and cost of ammunition, and simplify the firing process for increased firing rate, but the maturing technology has functionality issues. The projectile is the part of the ammunition that leaves the weapon and has the effect on the target. This effect is usually either kinetic (e.g., as with a standard bullet) or through

6162-434: 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),

6241-414: Was of relatively simple design and build (e.g., sling-shot, stones hurled by catapults), but as weapon designs developed (e.g., rifling ) and became more refined, the need for more specialized ammunition increased. Modern ammunition can vary significantly in quality but is usually manufactured to very high standards. For example, ammunition for hunting can be designed to expand inside a target, maximizing

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