Rotating bolt is a method of locking the breech (or rear barrel) of a firearm closed for firing.

Johann Nicolaus von Dreyse Johann Nicolaus von Dreyse (20 November 1787 – 9 December 1867) was a German firearms inventor and manufacturer. He is most famous for submitting the Dreyse needle gun in 1836 to the Prussian army, which was adopted for service in December 1840 ...

developed the first rotating bolt firearm, the "

Dreyse needle gun Dreyse may refer to: * Johann Nicolaus von Dreyse (1787–1867), German firearms inventor * Hitch Dreyse, a fictional List of Attack on Titan characters, character in ''Attack on Titan'' (''Shingeki no Kyojin'') series who serves in the military po ...

", in 1836. The Dreyse locked using the bolt handle rather than lugs on the bolt head like the Mauser M 98 or M16. The first rotating bolt rifle with two lugs on the bolt head was the Lebel Model 1886 rifle. The concept has been implemented on most firearms chambered for high-powered cartridges since the 20th century.

Design

Ferdinand Ritter von Mannlicher, who had earlier developed a non-rotating bolt straight-pull rifle, developed the Steyr-Mannlicher M1895, a straight-pull rifle with a rotating bolt, which was issued to the Austro-Hungarian Army. Mannlicher then developed the M1893 auto rifle which had a screw delayed bolt and later the Mannlicher M1900 operated by a gas piston. This was an inspiration for later gas operated, semi-automatic and selective fire firearms (such as the M1, M14, M16, the L85A1/A2 and the

AK-47 The AK-47, officially known as the Avtomat Kalashnikova (; also known as the Kalashnikov or just AK), is an assault rifle that is chambered for the 7.62×39mm cartridge. Developed in the Soviet Union by Russian small-arms designer Mikhail Kala ...

/ 74) in which the bolt, upon contact with the breech, rotates and locks into place, the lugs on the bolt locking into the breech or barrel extension. Upon closing, the bolt goes forward into

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden stave (wood), staves and bound by wooden or metal hoops. The word vat is often used for large containers ...

extension or locking recesses in the receiver, and then rotates; at this point it is locked in place. The bolt remains locked until the action is cycled, either manually by the operator, or mechanically by delayed blowback, recoil operation, or gas operation which then rotates the bolt and unlocks it from the breech so that it can be withdrawn in order to extract and eject the spent casing, and the next round can be chambered. In gas operation, the gas port, which meters a portion of the combustion gases into the action in order to cycle the weapon, is typically located either midway down the barrel or near the muzzle of the weapon. In this way it functions as a delay, ensuring that the bolt remains locked until chamber pressure has subsided to a safe level. Rotating bolts are found in gas-operated, recoil-operated, bolt action, lever-action, and

pump-action Pump action is a type of manual firearm action that is operated by moving a sliding handguard on the gun's forestock. When shooting, the sliding forend is pulled rearward to eject any expended cartridge (firearms), cartridge and typically to co ...

weapon designs.

Examples

M1 Garand The M1 Garand or M1 rifleOfficially designated as U.S. rifle, caliber .30, M1, later simply called Rifle, Caliber .30, M1, also called US Rifle, Cal. .30, M1 is a semi-automatic rifle that was the service rifle of the United States Army, U.S. ...

, gas-operated semi-automatic rifle * M25 Sniper Weapon System, semi-automatic rifle, gas operated, air cooled * Lebel Model 1886 rifle, bolt-action rifle * Steyr-Mannlicher M1895, a straight-pull rifle * M16, a gas-operated

rifle A rifle is a long gun, long-barreled firearm designed for accurate shooting and higher stopping power, with a gun barrel, barrel that has a helical or spiralling pattern of grooves (rifling) cut into the bore wall. In keeping with their focus o ...

, a gas-operated

* Oerlikon KBA 25mm, gas-operated autocannon * Imbel IA2, a gas-operated

assault rifle An assault rifle is a select fire rifle that uses an intermediate cartridge, intermediate-rifle cartridge and a Magazine (firearms), detachable magazine.C. Taylor, ''The Fighting Rifle: A Complete Study of the Rifle in Combat'', F.A. Moyer '' ...

* IWI Tavor TAR-21, a gas-operated

Ruger Mini-14 The Mini-14 is a lightweight semi-automatic rifle manufactured by Sturm, Ruger & Co. Introduced in 1973, the design was outwardly similar to the M14 rifle and is, in appearance, a scaled-down version chambered in 5.56×45mm NATO, though with its ...

, a gas-operated semi-automatic rifle * IMI Desert Eagle, one of the few

handgun A handgun is a firearm designed to be usable with only one hand. It is distinguished from a long gun, long barreled gun (i.e., carbine, rifle, shotgun, submachine gun, or machine gun) which typically is intended to be held by both hands and br ...

s with such mechanism. * Remington Model 8, a recoil-operated rifle * Chauchat, a recoil-operated light machine gun * Remington Model 7600, a pump-action rifle * The Winchester model 1200, 1300,and Super-X (SXP) Pump Shotguns * SIG-Sauer MPX, a gas-operated

submachine gun A submachine gun (SMG) is a magazine (firearms), magazine-fed automatic firearm, automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to descri ...

* CMMG MkG, the first AR15 derivative to use radial delayed blowback operation. * Browning BLR, a lever action rifle with a rotating bolt * L85A2, A variant of the L85A1 * S&T Motiv K16, a gas-operated general purpose machine gun

References

External links

{{commons category, Rotating bolt
Computer Animation demonstrating rotating bolt in the M16Primer actuated M16 using rotating bolt
Firearm components Firearm actions

Design

Examples

See also

References

External links