Rifling of a Canon de 75 modèle 1897

A 35 caliber Remington, with a microgroove rifled barrel with a right hand twist.

Rifling refers to helix-shaped pattern of grooves and lands that have been formed into the barrel of a firearm. It is the means by which a firearm imparts a spin to a projectile around its long axis, to gyroscopically stabilize it to improve accuracy and stability. Image File history File linksMetadata Download high-resolution version (3072x2048, 879 KB) Copyright © 2006 Med File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Firearm Rifling Canon de 75 modèle 1897 Metadata This file contains additional information, probably... Image File history File linksMetadata Download high-resolution version (3072x2048, 879 KB) Copyright © 2006 Med File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Firearm Rifling Canon de 75 modèle 1897 Metadata This file contains additional information, probably... Wikimedia Commons has media related to: Canon de 75 modèle 1897 Rifling of a 75 modèle 1897 The French 75mm field gun is a quick-firing field artillery piece developed before World War I and serving into World War II. It was commonly known as the French 75... Image File history File links Marlin_35_rem_2. ... Image File history File links Marlin_35_rem_2. ... Calibre redirects here. ... Remington Arms is a major American manufacturer of rifles, shotguns, other firearms, revolvers and ammunition. ... A helix (pl: helices), from the Greek word έλικας/έλιξ, is a twisted shape like a spring, screw or a spiral (correctly termed helical) staircase. ... Land may refer to: Land, the part of the Earth that is not covered by water Landform, a feature of the land Landscape, the layout, appearance and character of a land area Land bridge, a feature exposed during periods of low sea level A landing, A synonym for a region... This article does not cite its references or sources. ... Firearms redirects here. ... A gyroscope For other uses, see Gyroscope (disambiguation). ...

Twist rate

For best performance, the barrel should have a twist rate sufficient to stabilize any reasonable bullet that it would 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 "lever" to act on. The slowest twist rates are found in muzzleloading firearms meant to fire a round ball; these will have twist rates as low as 1 in 60 inches. The M16A2 rifle, which is designed to fire the SS109 bullet, has a 1 in 7 inch twist. Rifles, which generally fire longer, smaller diameter bullets, will in general have higher twist rates than handguns, which fire shorter, larger diameter bullets. This article is about firearms projectiles. ... This gyroscope remains upright while spinning due to its angular momentum. ... Muzzleloading is a term used to describe any firearm, but more particularly historical firearms, which are loaded at the muzzle, or open end of the gun barrel. ... M16 (more formally United States Rifle, Caliber 5. ... U.S. Military 5. ...

George Greenhill, a mathematician at Emmanuel College, Cambridge, UK, developed a rule of thumb for use in calculating twist rates for a given lead-core bullet. The formula, named the Greenhill Formula in his honour, is: of the Emmanuel College College name Emmanuel College Named after Jesus Christ (Emmanuel) Established 1584 Location St Andrews Street Admittance Men and women Master The Lord Wilson of Dinton Undergraduates 500 Graduates 100 Sister college Exeter College, Oxford College Website Boat Club Wesite Emmanuel front court and the Wren... A rule of thumb is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination. ...

where:

• C = 150 (use 180 for muzzle velocities higher than 2,800 f/s)
• D = bullet's diameter in inches
• L = bullet's length in inches
• SG = bullet's specific gravity (10.9 for lead-core bullets, which cancels out the second half of the equation)

The original value of C was 150, which yields a twist rate in inches per turn, when given the diameter D and the length L of the bullet in inches. This works to velocities of about 2800 f/s; above those velocities, a C of 180 should be used. For instance, with a velocity of 2000 f/s, a diameter of 0.5 inches and a length of 1.5 inches, the Greenhill formula would give a value of 30, which means 1 turn in 30 inches.

A Parrot Rifled Cannon. These were often used by both the Confederate and Union forces in the American Civil War.

If an insufficient twist rate is used, the bullet will begin to yaw and then tumble; this 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. Image File history File linksMetadata Size of this preview: 800 × 600 pixelsFull resolution (2816 × 2112 pixel, file size: 3. ... Image File history File linksMetadata Size of this preview: 800 × 600 pixelsFull resolution (2816 × 2112 pixel, file size: 3. ... A group of Confederate soldiers The Confederate States Army (CSA) was organized in February 1861 to defend the newly formed Confederate States of America from military action by the United States government during the American Civil War. ... The 21st Michigan Infantry, a company of Shermans veterans. ... Combatants United States of America (Union) Confederate States of America (Confederacy) Commanders Abraham Lincoln, Ulysses S. Grant Jefferson Davis, Robert E. Lee Strength 2,200,000 1,064,000 Casualties 110,000 killed in action, 360,000 total dead, 275,200 wounded 93,000 killed in action, 258,000 total... The word yaw can refer to: Yaw, the name for the Levantine god of chaos, rivers, the sea, and tempests; Yaw, an aeronautical and nautical term which indicates how far a craft is pointing away from its direction of travel due to rotation about its vertical axis. ... Precession redirects here. ...

Conversely, too-high rate of twist can also cause problems too. The excessive twist can cause accelerated barrel wear, and in high velocity bullets an excessive twist can cause bullets to literally tear themselves apart under the centripetal force. A higher twist than needed can also cause more subtle problems with accuracy: Any inconsistency in 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. Lastly, excessive spinning causes a reduction in the lateral kinetic energy of a projectile, thereby reducing its destructive power (the energy instead becomes rotational kinetic energy). The centripetal force is the external force required to make a body follow a circular path at constant speed. ... Concentric objects share the same center, axis or origin with one inside the other. ... coaxial cable In geometry, coaxial means that two or more forms share a common axis; it is the three-dimensional linear analog of concentric. Coaxial cable, as a common example, has a wire conductor in the center (D) a circumferential outer conductor (B) and an insulating medium called the dielectric... The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ...

Manufacture

A tank's main gun is often rifled.

Most rifling is created by either: Download high resolution version (1536x2048, 1257 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1536x2048, 1257 KB) Wikipedia does not have an article with this exact name. ...

• cutting one groove at a time with a machine tool, called cut rifling or single point cut rifling
• cutting all grooves in one pass with a special progressive broaching bit, called broached rifling
• pressing all grooves at once with a tool called a "button" that is pushed or pulled down the barrel, called button rifling
• forging the barrel over a mandrel containing a reverse image of the rifling (and often the chamber as well), called hammer forged
• flow forming the barrel preform over a mandrel containing a reverse image of the rifling, called rifling by flow forming. A new developed method by MACDOR company Turkey.

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' (turns per unit of barrel length). The spin imparted by rifling significantly improves 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 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 (see internal ballistics for more information on accuracy and bore characteristics). A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by machining, which is the selective removal of metal. ... A push style 5/16 keyway broach A broach is a series of chisel points mounted on one piece of steel. ... Power press with a fixed barrier guard A press, or a machine press is a tool used to work metal (typically steel) by changing its shape and internal structure. ... For finery forges (making iron), see finery forge. ... The barrel of a firearm is the tube, usually metal, through which a controlled explosion is released in order to propel a projectile out of the end at great speed. ... A mandrel (pronounced , and also spelled mandril; in American English also called an arbor) is either an object used to shape machined work; a tool component that grips or clamps materials to be machined; or a tool component that can be used to grip other moving tool components. ... Flow Forming is a metal production procedure that turns the metal over a special mandrel and hydraulic rollers using tremendous pressure. ... For other uses, see Barrel (disambiguation). ... A mandrel (pronounced , and also spelled mandril; in American English also called an arbor) is either an object used to shape machined work; a tool component that grips or clamps materials to be machined; or a tool component that can be used to grip other moving tool components. ... Land may refer to: Land, the part of the Earth that is not covered by water Landform, a feature of the land Landscape, the layout, appearance and character of a land area Land bridge, a feature exposed during periods of low sea level A landing, A synonym for a region... Twist rate is a gun term that refers to the rate of twist of a gun barrels rifling grooves. ... A gunsmith is a person who designs, builds, repairs or modifies firearms to blueprint and customer specifications, using hand tools and machine tools such as grinders and lathes. ... A lathe is a common tool used in machining. ... Internal ballistics, a subfield of ballistics, is the study of a projectiles behavior from the time its propellants igniter is initiated until it exits the gun barrel. ...

Typically in small firearms, the diameter of the bullet matches the diameter of the circle that encompasses the bottoms of the rifled grooves, the groove diameter. The bore diameter is the measure across the tops of the lands. When the cartridge is fired, the bullet is forced into the barrel and the rifling engages the bullet, engraving it with an impression of the rifling. As the bullet is propelled down the barrel, it begins to spin. This rate of spin is dictated by a bullet's muzzle velocity and the twist rate of the rifling. As mentioned earlier, for a given caliber, faster rates of twist are needed to stabilize longer bullets. Land may refer to: Land, the part of the Earth that is not covered by water Landform, a feature of the land Landscape, the layout, appearance and character of a land area Land bridge, a feature exposed during periods of low sea level A landing, A synonym for a region... Rimmed, centerfire . ... Twist rate is a gun term that refers to the rate of twist of a gun barrels rifling grooves. ...

Bullets fired from a rifled barrel should ideally be at or slightly under the groove diameter, and definitely larger than the bore diameter. A bullet that is too large will have to swage down to fit in the bore, which can cause excessive pressures, while a bullet that is too small will either leak gas or obturate at an angle, both of which will provide poor accuracy. Swaging is a metal forming technique in which the metal is plastically deformed to its final shape using high pressures. ... Obturate means to block or obstruct. ...

History

The history of rifling a barrel is covered in depth in the article Rifle. For other uses, see Rifle (disambiguation). ...

Recent developments

The grooves most commonly used in modern rifling have fairly sharp edges. More recently, polygonal rifling, 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 reduces erosion of the barrel. Supporters of polygonal rifling also claim higher velocities and greater accuracy. Polygonal rifling is currently seen on pistols from Heckler & Koch, Glock and Kahr Arms, as well as the Desert Eagle. Conventional eight groove rifling on the left, and octagonal polygonal rifling on the right. ... A Browning 9 millimeter Hi-Power Ordnance pistol of the French Navy, 19th century, using a Percussion cap mechanism Derringers were small and easily hidden. ... Heckler & Koch GmbH (H&K) (pronounced [1]) is a German weapons manufacturing company famous for various series of small firearms, notably the MP5 submachine gun, the MP7 personal defense weapon, USP series of handguns, high-precision PSG1 sniper rifle, and the G3 and G36 assault rifles. ... Glock is an Austrian weapons manufacturer (named after the founder Gaston Glock) founded in 1963 in Deutsch-Wagram, near Vienna, Austria. ... Kahr Arms is a small arms manufacturer with a 22,000 sq. ... The Desert Eagle is a large caliber gas-operated semi-automatic pistol manufactured in Israel by IMI (Israel Military Industries) for Magnum Research, Inc. ...

For tanks and artillery pieces, the extended range, full bore concept developed by Gerald Bull for the GC-45 howitzer reverses the normal rifling idea by using a shell with small fins that ride in the grooves, as opposed to using a slightly oversized projectile which is forced into the grooves. Such guns have achieved significant increases in muzzle velocity and range. Examples include the South African G5 and the German PzH 2000. Gerald Vincent Bull (March 9, 1928 - March 22, 1990) was a Canadian engineer who developed long range artillery. ... The GC-45 (Gun, Canada, 45-calibre) is a 155 mm howitzer designed by Gerald Bulls Space Research Corporation in the 1970s. ... The G5 is a South African towed howitzer produced by Denel. ... The Panzerhaubitze 2000 (English. ...

References

This article does not cite any references or sources. (December 2006) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

Image File history File links Question_book-3. ...

See also

• Comparison Microscope

A comparison microscope, sometimes known also as stereomicroscope or dissecting microscope, is a device used to analyze side-by-side specimens. ...

External links

• THE MAKING OF A RIFLED BARREL by Geoffrey Kolbe
• Article on barrel making from an IHMSA shooter
• Rifling By Flow Forming A new developed method for rifling.
• Article on barrel making from Lilja, a maker of world class competition barrels
• Article on making and measuring rifling by Lilja; includes pictures of button rifling machine
• 6mmBR article on barrels
• Bore slugging tutorial, explaining now to determine the true bore and groove size and choose appropriate bullet diameters