Breechblock
Encyclopedia
A breechblock is the part of the firearm action
that closes the breech of a weapon (whether small arms or artillery) at the moment of firing.
Most modern small firearms use a rotating breechblock
, better known as a bolt, first used in manually operated bolt action weapons, but later operated by the power of the cartridge in automatic weapons. Some variations of non-rotating breechblocks include:
In artillery the forces are much greater, but similar methods are used. The Welin breech block
uses an interrupted screw
and is used on weapons with calibres from about 4 inches up to 16 inches or more. Other systems use horizontal or vertical sliding block.
Firearm action
In firearms terminology, an action is the physical mechanism that manipulates cartridges and/or seals the breech. The term is also used to describe the method in which cartridges are loaded, locked, and extracted from the mechanism. Actions are generally categorized by the type of mechanism used...
that closes the breech of a weapon (whether small arms or artillery) at the moment of firing.
Most modern small firearms use a rotating breechblock
Rotating bolt
Rotating bolt is a method of locking originally developed by Ferdinand Ritter von Mannlicher and found in his Steyr-Mannlicher M1895 straight-pull bolt-action rifle designed for and issued to the Austro-Hungarian Army...
, better known as a bolt, first used in manually operated bolt action weapons, but later operated by the power of the cartridge in automatic weapons. Some variations of non-rotating breechblocks include:
- BlowbackBlowback (arms)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 gases created by the ignition of the propellant charge....
breechblock - in which the breechblock is closed by a powerful spring. A variation of this is the "Delayed blowback" found in many weapons from Heckler & KochHeckler & KochHeckler & Koch GmbH is a German defense manufacturing company that produces various small arms. Some of their products include the SA80, MP5 submachine gun, G3 automatic rifle, the G36 assault rifle, the HK 416, the MP7 personal defense weapon, the USP series of handguns, and the high-precision... - Tilting breechblock - both self-actuating (AG-42 Ljungman is one example) and manually operated by a lever (Peabody actionPeabody actionThe Peabody action was an early form of breechloading firearm action, where the heavy breechblock tilted downwards across a bolt mounted in the rear of the breechblock, operated by a lever under the rifle. The Peabody action most often used an external hammer to fire the cartridge.The Peabody...
) or other means (Krag-PeterssonKrag-PeterssonThe Krag-Petersson rifle was the first repeating rifle adopted by the armed forces of Norway and one of the first repeating arms used anywhere in the world. Developed by Ole Herman Johannes Krag, the action of the Krag-Petersson was uniquely actuated by an oversized hammer...
) - Falling block (Sharps rifleSharps RifleSharps rifles were those of a series begun with a design by Christian Sharps. Sharps rifles were renowned for long range and high accuracy in their day.-History:Sharps's initial rifle was patented September 17, 1848 and manufactured by A. S...
) - Floating breechFloating breechA floating breech is a breechblock of a firearm that is not held rigidly to the barrel at the moment of firing, but instead is free to move in the opposite direction to the projectile...
- Rolling blockRolling blockA rolling block is a form of firearm action where the sealing of the breech is done with a specially shaped breechblock able to rotate on a pin. The breechblock is shaped like a section of a circle....
(RemingtonRemington M1867The Remington rolling block M1867 was the first truly modern rifle to be adopted by the Norwegian Army. Nominally it had a caliber of 4 Norwegian decimal lines, the actual caliber was 3.88 Norwegian decimal lines , and it fired an 12.615 mm rimfire round.-Birth of the M1867:In the 1860s the...
) - Hinged breechblock (Snider-EnfieldSnider-EnfieldThe British .577 Snider-Enfield was a type of breech loading rifle. The firearm action was invented by the American Jacob Snider, and the Snider-Enfield was one of the most widely used of the Snider varieties. It was adopted by British Army as a conversion system for its ubiquitous Pattern 1853...
, Springfield rifleSpringfield Model 1873The Model 1873 "Trapdoor" Springfield was the first standard-issued breech-loading rifle adopted by the United States Army...
) - Screwed breechblock (Ferguson rifleFerguson rifleThe Ferguson rifle was one of the first breech loading rifles to be widely tested by the British military. Other breech loaders were experimented with in various commands, including earlier versions of the Ordnance rifle by Patrick Ferguson when he was in the "Fever Islands" . It was often...
)
In artillery the forces are much greater, but similar methods are used. The Welin breech block
Welin breech block
The Welin breech block was a revolutionary stepped, interrupted thread design for locking artillery breeches, invented by Axel Welin in 1889 or 1890...
uses an interrupted screw
Interrupted screw
An interrupted screw or interrupted thread is a mechanical device typically used in the breech of artillery guns. It was invented circa 1845....
and is used on weapons with calibres from about 4 inches up to 16 inches or more. Other systems use horizontal or vertical sliding block.