Rotating bolt

Last updated
M16 bolt locking fig 2-6.png
M16 bolt locking
M16 bolt unlocking fig 2-8.png
M16 bolt unlocking
Rotating Bolt.png
Radial-delayed blowback. Kinematik Ruckdrucklader ubersetzter Drehkopfverschluss mit Schleuderkurve CY BY-SA 4.0 by Grasyl.svg
Radial-delayed blowback.

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

Contents

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-47/74) 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 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recoil operation, or gas operation which then rotates the bolt and unlocks it from the breech so that it can be withdrawn in order to extract and eject the spent casing, and the next round can be chambered.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 delayed blowback, gas-operated, recoil-operated, bolt action, lever-action, and pump-action weapon designs. In some forms of delayed blowback, the rotating bolt is used as the delay mechanism: 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

See also

Related Research Articles

<span class="mw-page-title-main">Semi-automatic rifle</span> Type of autoloading 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. In contrast, a bolt-action rifle requires the user to cycle the bolt manually before they can fire a second time, and a fully automatic rifle fires continuously until the trigger is released.

<span class="mw-page-title-main">Bolt action</span> Type of firearm mechanism

Bolt-action is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, most commonly placed on the right-hand side of the firearm. The majority of bolt-action firearms are rifles, but there are also some variants of shotguns and handguns that are bolt-action.

<span class="mw-page-title-main">Action (firearms)</span> Functional mechanism of breech-loading

In firearms terminology, an action is the functional mechanism of a breech-loading firearm that handles the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock.

A semi-automatic firearm, also called a self-loading or autoloading firearm, is a repeating firearm whose action mechanism automatically loads a following round of cartridge into the chamber and prepares it for subsequent firing, but requires the shooter to manually actuate the trigger in order to discharge each shot. Typically, this involves the weapon's action utilizing the excess energy released during the preceding shot to unlock and move the bolt, extracting and ejecting the spent cartridge case from the chamber, re-cocking the firing mechanism, and loading a new cartridge into the firing chamber, all without input from the user. To fire again, however, the user must actively release the trigger, allow it to "reset", before pulling the trigger again to fire off the next round. As a result, each trigger pull only discharges a single round from a semi-automatic weapon, as opposed to a fully automatic weapon, which will shoot continuously as long as the ammunition is replete and the trigger is kept depressed.

<span class="mw-page-title-main">Semi-automatic pistol</span> Type of pistol

A semi-automatic pistol is a handgun that automatically ejects and loads cartridges in its chamber after every shot fired. Only one round of ammunition is fired each time the trigger is pulled, as the pistol's fire control group disconnects the trigger mechanism from the firing pin/striker until the trigger has been released and reset.

A repeating rifle is a single-barreled rifle capable of repeated discharges between each ammunition reload. This is typically achieved by having multiple cartridges stored in a magazine and then fed individually into the chamber by a reciprocating bolt, via either a manual or automatic action mechanism, while the act of chambering the round typically also recocks the hammer/striker for the following shot. In common usage, the term "repeating rifle" most often refers specifically to manual repeating rifles, as opposed to self-loading rifles, which use the recoil, gas, or blowback of the previous shot to cycle the action and load the next round, even though all self-loading firearms are technically a subcategory of repeating firearms.

<span class="mw-page-title-main">Desert Eagle</span> Semi-automatic pistol

The Desert Eagle is a single-action, gas-operated, semi-automatic pistol known for chambering the .50 Action Express, the largest centerfire cartridge of any magazine-fed, self-loading pistol.

Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge.

<span class="mw-page-title-main">Breechblock</span> Part of the firearm action

A breechblock is the part of the firearm action that closes the breech of a breech loading weapon before or at the moment of firing. It seals the breech and contains the pressure generated by the ignited propellant. Retracting the breechblock allows the chamber to be loaded with a cartridge.

<span class="mw-page-title-main">Gas-operated reloading</span> System of operation used to provide energy to operate autoloading firearms

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 case and insert a new cartridge into the chamber. Energy from the gas is harnessed through either a port in the barrel or a trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.

<span class="mw-page-title-main">Ferdinand Mannlicher</span> Austrian firearms designer (1848 - 1904)

Ferdinand Ritter von Mannlicher was an Austrian engineer and small arms designer. Along with James Paris Lee, Mannlicher was particularly noted for inventing the en-bloc clip charger-loading box magazine system. Later, while making improvements to other inventors' prototype designs for rotary-feed magazines, Mannlicher, together with his protégé Otto Schönauer, patented a perfected rotary magazine design, the Mannlicher–Schönauer rifle, which was a commercial and military success.

<span class="mw-page-title-main">Bolt (firearms)</span>

A bolt is the part of a repeating, breechloading firearm that blocks the rear opening (breech) of the barrel chamber while the propellant burns, and moves back and forward to facilitate loading/unloading of cartridges from the magazine. The firing pin and extractor are often integral parts of the bolt. The terms "breechblock" and "bolt" are often used interchangeably or without a clear distinction, though usually, a bolt is a type of breechblock that has a nominally circular cross-section.

<span class="mw-page-title-main">Locked breech</span>

Locked breech is the design of a breech-reloading firearm's action. This is important in understanding how a self-reloading firearm works. In the simplest terms, the locked breech is one way to slow down the opening of the breech of a self-reloading firearm when fired. The source of power for the movement is recoil.

<span class="mw-page-title-main">Blank-firing adapter</span> Firearms safety device for projectile-less cartridges

A blank-firing adapter or blank-firing attachment (BFA), sometimes called a blank adapter or blank attachment, is a device used in conjunction with blank ammunition for safety reasons, functional reasons or a combination of them both. Blank firing adapters are required for allowing blank ammunition to cycle the bolts of most semi-automatic and automatic firearms. It can also be a safety feature designed to break up the plugs replacing the bullet in military blanks as well as divert the hot gases from a blank discharge out to the sides, reducing the risk of injury to the target of an aimed shot.

<span class="mw-page-title-main">Volkssturmgewehr</span> Semi-automatic rifle

The Volkssturmgewehr is the name of several rifle designs developed by Nazi Germany during the last months of World War II. They share the common characteristic of being greatly simplified as an attempt to cope with severe lack of resources and industrial capacity in Germany during the final period of the war. The Volkspistole was a partner program, almost identical, but for pistols instead.

The following are terms related to firearms and ammunition topics.

<span class="mw-page-title-main">Blow forward</span> Type of firearm action

Blow forward is a firearm action where the propellant gas pressure and the friction of the bullet traveling down the bore drag the whole gun barrel forward to facilitate the opening of the breech. This forward barrel motion provides most of the energy required to eject a spent cartridge case and chamber a fresh round of ammunition, and contains a minimum of moving parts, and thus is more compact than other operating mechanisms of equal barrel length.

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 propellant gas.

<span class="mw-page-title-main">Tilting bolt</span> Locking mechanism used in self-reloading firearms and straight-pull repeating rifles

Tilting bolt action is a type of locking mechanism often used in self-loading firearms and, rarely, in straight-pull repeating rifles. Essentially, the design consists of a moving bolt driven by some mechanism, most often a piston with gas pressure from the gas port behind the muzzle. The bolt drops down into receiver recess and locks on bolt closing. Tilting the bolt up and down locks-unlocks in the breech. This tilting allows gas pressure in the barrel from firing the gun to lower to safe levels before the cartridge case is ejected.

<span class="mw-page-title-main">Repeating firearm</span> Firearms that can be discharged multiple times after a single ammunition reload

A repeating firearm or repeater is any firearm that is capable of being fired repeatedly before having to be manually reloaded with new ammunition into the firearm.

References

  1. Walter, John (2006). Rifles of the World (3rd ed.). Iola, WI: Krause Publications. p. 142. ISBN   978-0-89689-241-5.
  2. Sweeney, Patrick (2010). The Gun Digest Book of The AR-15 (Vol. 3.). Iola, WI: Gun Digest Books. p. 20. ISBN   978-1440213762.
  3. "Automatisch kanon Oerlikon KBA". Nationaal Militair Museum (in Dutch). Retrieved 2024-03-20.
  4. Modern Firearms – TAR-21 assault rifle Archived 2004-10-12 at the Wayback Machine . World.guns.ru. Retrieved on 2024-03-21.
  5. Hogg, Ian (2000-02-10). Military Small Arms of the 20th Century. Krause Publications. ISBN   978-0-87341-824-9.
  6. Ayoob, Massad (14 May 2014). Gun Digest Book of SIG-Sauer. Iola, Wisconsin: F+W Media. ISBN   978-1-4402-3920-5.