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", in 1836. The Dreyse locked using the bolt handle rather than lugs on the bolt head like the
Mauser M 98
The Mauser M 98 are a series of currently (2020) produced bolt-action hunting rifles.
The production of the controlled round feed Mauser 98 bolt action system for the German military ceased at the end of World War II in 1945. The new Mauser M 98 ...
or
M16
The M16 rifle (officially designated Rifle, Caliber 5.56 mm, M16) is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56×45mm automatic rifle with a 20-roun ...
. The first rotating bolt rifle with two lugs on the bolt head was the
Lebel Model 1886 rifle
The Lebel Model 1886 rifle (French: ''Fusil Modèle 1886 dit "Fusil Lebel"'') also known as the ''"Fusil Mle 1886 M93"'', after a bolt modification was added in 1893, is an 8 mm bolt-action infantry rifle that entered service in the French A ...
. 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
The Mannlicher M1895 (german: link=no, Infanterie Repetier-Gewehr M.95, hu, Gyalogsági Ismétlő Puska M95; "Infantry Repeating-Rifle M95") is a straight pull bolt-action rifle, designed by Ferdinand Ritter von Mannlicher that used a refined ...
, 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 M16 rifle (officially designated Rifle, Caliber 5.56 mm, M16) is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56×45mm automatic rifle with a 20-roun ...
, the
L85A1/A2 and the
AK-47/
74) in which the
bolt, upon contact with the
breech
Breech may refer to:
* Breech (firearms), the opening at the rear of a gun barrel where the cartridge is inserted in a breech-loading weapon
* breech, the lower part of a pulley block
* breech, the penetration of a boiler where exhaust gases leave ...
, 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 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
Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent ...
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
delayed blowback,
gas-operated,
recoil-operated
Recoil operation is an operating mechanism used to implement locked breech, autoloading firearms. Recoil operated firearms use the energy of recoil to cycle the action, as opposed to gas operation or blowback operation using the pressure of the ...
,
bolt action,
lever-action and
pump-action
Pump action or slide action is a repeating firearm action that is operated manually by moving a sliding handguard on the gun's forestock. When shooting, the sliding forend is pulled rearward to eject any expended cartridge and typically to co ...
weapon designs. Another form of
delayed blowback which the bolt head rotates as the firing pin strikes locking the chamber until the gas pressure reaches a safe level to extract. As the firing pin retracts, the bolt head turns anti-clockwise unlocking the breech.
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 U.S Army during World W ...
, gas-operated
semi-automatic rifle
A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger, and uses part of the fired cartridge's energy to eject the case and load another cartridge into the chamber. For comparison, a bolt ...
*
M25 Sniper Weapon System,
semi-automatic rifle
A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger, and uses part of the fired cartridge's energy to eject the case and load another cartridge into the chamber. For comparison, a bolt ...
, gas operated, air cooled
*
Lebel Model 1886 rifle
The Lebel Model 1886 rifle (French: ''Fusil Modèle 1886 dit "Fusil Lebel"'') also known as the ''"Fusil Mle 1886 M93"'', after a bolt modification was added in 1893, is an 8 mm bolt-action infantry rifle that entered service in the French A ...
, bolt-action rifle
*
Steyr-Mannlicher M1895
The Mannlicher M1895 (german: link=no, Infanterie Repetier-Gewehr M.95, hu, Gyalogsági Ismétlő Puska M95; "Infantry Repeating-Rifle M95") is a straight pull bolt-action rifle, designed by Ferdinand Ritter von Mannlicher that used a refined ...
, a straight-pull rifle
*
M16
The M16 rifle (officially designated Rifle, Caliber 5.56 mm, M16) is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56×45mm automatic rifle with a 20-roun ...
, a gas-operated
rifle
*
AK-47, a gas-operated
rifle
*
Oerlikon KBA 25mm, gas-operated autocannon
*
Imbel IA2, a gas-operated
assault rifle
*
IWI Tavor TAR-21
The IWI Tavor TAR-21 is an Israeli bullpup assault rifle chambered in 5.56×45mm NATO caliber with a selective fire system, selecting between semi-automatic mode and full automatic fire mode. The Tavor is designed and produced by Israel Weapo ...
, a gas-operated
assault rifle
*
Ruger Mini-14, a gas-operated
semi-automatic rifle
A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger, and uses part of the fired cartridge's energy to eject the case and load another cartridge into the chamber. For comparison, a bolt ...
*
IMI Desert Eagle
The Desert Eagle is a gas-operated, semi-automatic pistol known for chambering the .50 Action Express, the largest centerfire cartridge of any magazine-fed, self-loading pistol.
Magnum Research Inc. (MRI) designed and developed the Desert Eagle ...
, one of the few
handguns 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-fed, 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 describe its design concept as an autom ...
*
CMMG Mk 45 Guard, the first AR15 derivative to use radial delayed blowback operation.
*
Browning BLR, a
lever action rifle with a rotating bolt
*
L85A2
The SA80 (Small Arms for the 1980s) is a British family of 5.56×45mm NATO service weapons used by the British Army. The L85 Rifle variant has been the standard issue service rifle of the British Armed Forces since 1987, replacing the L1A1 Se ...
, A variant of the L85A1
See also
*
Roller locked
In firearms operating systems, the term roller locked refers to locking the bolt with rollers. Notable examples of firearms using this method are the MG 42 general-purpose machine gun, and the CZ 52 semi-automatic pistol. It was also applied in ...
External links
Computer Animation demonstrating rotating bolt in the M16Primer actuated M16 using rotating bolt
{{commonscat, Rotating bolt
Firearm components
Firearm actions