Gun barrel
A gun barrel is a crucial part of
The first firearms were made at a time when metallurgy was not advanced enough to cast tubes capable of withstanding the explosive forces of early cannons, so the pipe (often built from staves of metal) needed to be braced periodically along its length for structural reinforcement, producing an appearance somewhat reminiscent of storage barrels being stacked together, hence the English name.[1]
History
Gun barrels are usually made of some type of metal or
Early
Early cannon barrels were very thick for their caliber. This was because manufacturing defects such as air bubbles trapped in the metal were common at that time, and played key factors in many gun explosions; these defects made the barrel too weak to withstand the pressures of firing, causing it to fail and fragment explosively.[7]
Construction
A gun barrel must be able to hold in the expanding gas produced by the
Fluting
Fluting is the removal of material from a cylindrical surface, usually creating rounded grooves, for the purpose of reducing weight. This is most often done to the exterior surface of a rifle barrel, though it may also be applied to the
While the main purpose of fluting is just to reduce weight and improve portability, when adequately done it can retain the
Composite barrels
A composite barrel is a firearm barrel that has been shaved down to be thinner and an exterior sleeve slipped over and fused to it that improves rigidity, weight and cooling. Most common form of composite barrel are those with
Mounting
A barrel can be fixed to the receiver using
Components
Chamber
The chamber is the cavity at the back end of a
Structurally, the chamber consists of the body, shoulder and neck, the contour of which closely correspond to the casing shape of the cartridge it is designed to hold. The rear opening of the chamber is the breech of the whole barrel, which is sealed tight from behind by the
Chambering a gun is the process of loading a cartridge into the gun's chamber, either manually as in
In the context of firearms design, manufacturing and modification, the word "chambering" has a different meaning, and refers to fitting a weapon's chamber specifically to fire a particular caliber or model of cartridge.
Bore
The bore is the hollow internal
Most modern firearms (except
When a firearm cartridge is chambered, its casing occupies the chamber but its bullet actually protrudes beyond the chamber into the posterior end of the bore. Even in a rifled bore, this short rear section is without rifling, and allows the bullet an initial "run-up" to build up momentum before encountering riflings during shooting. The most posterior part of this unrifled section is called a freebore, and is usually cylindrical. The portion of the unrifled bore immediately front of the freebore, called the leade, starts to taper slightly and guides the bullet towards the area where the riflingless bore transitions into fully rifled bore. Together they form the throat region, where the riflings impactfully "bite" into the moving bullet during shooting. The throat is subjected to the greatest thermomechanical stress and therefore suffers wear the fastest. Throat erosion is often the main determining factor of a gun's barrel life.
Muzzle
The muzzle is the front end of a barrel from which the projectile will exit.[11] Precise machining of the muzzle is crucial to accuracy, because it is the last point of contact between the barrel and the projectile. If inconsistent gaps exist between the muzzle and the projectile, escaping propellant gases may spread unevenly and deflect the projectile from its intended path (see transitional ballistics). The muzzle can also be threaded on the outside to allow the attachment of different accessory devices.
In rifled barrels, the contour of a muzzle is designed to keep the rifling safe from damage by intruding foreign objects, so the front ends of the rifling grooves are commonly protected behind a recessed crown, which also serves to modulate the even expansion of the propellant gases. The crown itself is often recessed from the outside rim of the muzzle to avoid accidental damage from collision with the surrounding environment.
In
During firing, a bright flash of light known as a muzzle flash is often seen at the muzzle. This flash is produced by both superheated propellant gases radiating energy during expansion (primary flash), and the incompletely combusted propellant residues reacting vigorously with the fresh supply of ambient air upon escaping the barrel (secondary flash). The size of the flash depends on factors such as barrel length (shorter barrels have less time for complete combustion, hence more unburnt powder), the type (fast- vs. slow-burning) and amount of propellant (higher total amount means likely more unburnt residues) loaded in the cartridge. Flash suppressors or muzzle shrouds can be attached to the muzzle of the weapon to either diminish or conceal the flash.[11]
The rapid expansion of propellant gases at the muzzle during firing also produce a powerful
See also
- Bore evacuator
- Bore snake
- Cap gun
- Caplock mechanism
- Minié ball
- Muzzleloader
- Polygonal rifling
- Slug barrel
- Tubes and primers for ammunition
References
- ^ A History of Warfare - Keegan, John, Vintage 1993.
- ISBN 978-0-8225-3805-9.
- ISBN 978-0-87021-009-9.
- ISBN 978-1-4262-0544-6.
- ISBN 978-1-4402-1787-6.
- ISBN 978-0-8263-5002-2.
- ISBN 978-1-85109-556-8.
- ISBN 978-1-56414-756-1.
- ISBN 978-1-59114-658-2.
- ^ https://patents.google.com/patent/US2901814A/en
- ^ a b Quertermous & Quertermous, p. 429 f.
Bibliography
- Quertermous, Russell C.; Quertermous, Steven C. (1981). Modern Guns (Revised 3rd ed.). Paducah, Kentucky: Collector Books. ISBN 0-89145-146-3.