The barrel of a firearm , which is used to guide the projectile and hold the propellant charge or cartridge , is generally referred to as the barrel . In the strict sense, barrel only refers to the section of the gun barrel that the projectile travels through when it is fired. The rear end of the barrel into which the cartridge is loaded is called the cartridge chamber. The bore of the barrel is also referred to as the soul ( barrel soul ), its longitudinal axis as the soul axis .
Development, designs, manufacture
High demands are placed on the running material. The material must be strong enough to withstand pressures of up to several thousand bar without permanent deformation; however, it must not be too hard either, as otherwise brittle fractures can occur.
The first barrels of handguns consisted of a tube made from a steel plate about 10 mm thick that was forged around a mandrel and welded lengthways. The straight seam placed tight limits on the compressive strength of the barrel. This was countered by giving the seam a spiral course by twisting the barrel. Later, barrels were made of steel strip wound spirally around a mandrel and then welded. After that, flat steels made of Damascus steel were used to manufacture the barrel , which led to a further increase in the strength of the barrels.
The barrels of early guns are often split in two. In the front area was the flight for receiving the projectile and behind it was the chamber with a smaller caliber for receiving the powder charge.
Modern barrels are made of steel that is alloyed with nickel , chromium , molybdenum , silicon or other additives. There have been isolated attempts to manufacture barrels for handguns from special ceramic materials, but these projects have not yet reached series production (see Lightweight Small Arms Technologies ).
Since the beginning of the industrial mass production of barrels, barrel blanks have been manufactured by forging , reworked, tempered and then drilled using a deep drilling machine. The surface of the bore was then smoothed by rubbing and, in the case of rifle barrels, provided with trains. Cables are either cut with a pull rod or pressed into the barrel wall without cutting.
Rifle and shotgun barrels are now made on a large scale by hammering . Here, a short, deep-drilled blank is passed over a polished and hardened mandrel, the diameter of which corresponds to the barrel bore, and brought to the intended length and shape by machine hot or cold hammering . With this method, some otherwise necessary processing steps , such as tempering , can be dispensed with. When cold hammering rifle barrels, the shape of the mandrel corresponds to the negative shape of the barrel including the rifles, so that no further work steps are necessary to incorporate the rifle.
The barrels of earlier guns consisted of tubular wrought iron rods, which were held together by steel bands similar to a barrel ( bar ring gun ). These were replaced by pipes made of bronze or cast iron. With the advancement of metallurgy and the beginning of industrialization , gun barrels have been made exclusively of steel since the 19th century.
The goal in the construction of gun barrels was to achieve ever greater gas pressures and thus more power. Attempts were initially made to reinforce the solid pipes with greater wall thickness, but this was only possible to a limited extent. At some point, the material thickness of the pipe has little influence on the load on the inner wall of the pipe. In the 19th century it was recognized that external pressure on the pipe counteracted the expansion pressure of the powder gases. The multilayer pipes were created on this principle . Here steel jackets (sheath tube) were steel rings (annulus), or combinations of both (shroud tube) or steel wire or band ( wire tube ) to the core tube is shrunk . After cooling, these layers created a constant pressure on the core tube. Multi-layer pipes remained in use until they were gradually replaced by the autofrettage discovered at the beginning of the 20th century .
The inside of the barrel is exposed to very high levels of abrasion and erosion from hot powder residues. The inside of the barrel can therefore be provided with various coatings to increase their service life, for example hard chrome plating of the inside of the barrel is possible with handguns . This coating also makes it easier to remove bullet wear and powder smoke and prevents corrosion . The barrels of some heavy machine weapons and artillery are lined with very resistant alloys such as stellite to reduce wear .
In the case of machine guns, in particular, a bullet delivery capability is often required for reasons of handling safety, and a further bullet from a cartridge that is fired at one that is stuck in the barrel must not burst the barrel. This can happen, for example, if there is no propellant charge in a cartridge, only the primer or a charge that is too weak drives the projectile into the barrel or there are foreign objects in the barrel and block the projectile.
Today's barrels have different shapes of the inner cross-section depending on the intended use. The barrels of shotguns and smoothbore guns have a smooth inner wall. From these barrels stabilized projectiles or projectiles (e.g. shotgun pellets ) are fired with aerodynamic means (stabilization surfaces) . Shotgun barrels often have a barrel narrowing ( choke hole ) in the area of the muzzle in order to influence the dispersion of the shot or to achieve a more favorable grouping of the shot sheaf.
Barrels of guns and rifles with rifled barrels have spirally cut or pressed lines into the inside of the barrel , the spiral course of which gives the projectiles a twist and thus stabilizes them. A special form is the polygon course , which instead of sharp-edged features has an inner cross-section shaped as a polygon.
Since the beginning of the 20th century, attempts have been made with conical barrels to achieve higher initial speeds. The New Zealander Russell Robinson developed squeeze caliber cartridges in the 1940s , but further testing did not begin until around 1962 after NATO stopped the development of duplex and triplex bullets .
Squeeze caliber cartridges are fired from weapons with conical barrels, i.e. barrels tapering towards the muzzle. The bullet is compressed in the course of this. The cross-sectional area of the bullet is reduced to about a third to a quarter. In particular, the caliber .50: .30 (about 12.7 mm by 7.62 mm) and .30: .15 were tested.
A .45: .38 caliber pistol was also developed by Colt. The associated cartridge contained three projectiles each weighing 5.2 g.
Some anti-tank weapons such as the 7.5 cm PaK 41 , the Panzerbüchse 41 or the 4.2 cm light PaK 41 had conical barrels in order to be able to fire projectiles with the highest possible muzzle velocity . The barrel of the anti-tank rifle tapered continuously up to the muzzle, while the barrel of the PaK narrowed in a replaceable section of the barrel. During the Second World War there were also attempts on the German side to equip barrels with exchangeable muzzle inserts that had conical or cylindrical bores depending on the type of bullet required.
Exchange barrels within the meaning of the German Weapons Act (WaffG) are barrels for a specific weapon model that can be changed without reworking ( WaffG). These are often sets for sport pistols with special properties (barrel length, weight).
Exchange barrels within the meaning of the WaffG are barrels for a specific weapon model that must be adapted to the respective weapon (Appendix 1, section 3.2 WaffG). Exchangeable barrels are used as a replacement for a damaged or worn barrel, for example.
In the military sector, air-cooled machine guns in particular are often equipped with barrels that can be changed quickly. This allows the soldier to quickly exchange a hot barrel for a cold one and then continue shooting immediately. Exchange barrels are often used here, even though they are actually exchange barrels in the sense of the WaffG.
Double and over-and-under rifles or shotguns, so-called triplets for hunting and historical pistols with two barrels are known. Three-of-a-kind shot barrels (smooth tubes) are usually connected to a rifled barrel below.
Weapons with barrel bundles are mostly black powder pistols, with which, depending on the design, up to ten projectiles are fired at the same time or one after the other from a corresponding number of parallel barrels. Also known is the mitrailleuse , a cannon in whose massive barrel no gun barrel, but up to 50 parallel rifle-caliber barrels were drilled, which fired simultaneously.
In Gatling guns , several cycles turn, but always shoots only one. In the Gatling, the barrel set was turned with a hand crank. During one rotation of the barrel assembly, the empty cartridge case is pulled out of the fired barrel and a new one is inserted. This is possible because every single barrel has its own lock, which is operated by a fixed cam. This allows the weapon to reach a higher rate of cadence and the (usually six to eight) barrels do not heat up as quickly. A well-known weapon of this type is the US “ Minigun ” MG in 7.62 mm caliber , in which the barrel set is rotated by an electric motor.
Barrels must be cleaned of impurities. There are deposits that are created by abrasion of the projectiles , as well as residues that result from the combustion of the ignition and propellants and can cause corrosion. These are wiping sticks used in various forms.
Barrel vibrations in precision weapons
Barrels swing radially and axially when the shot is fired . The vibrations are caused by the advance caused by the propellant charge and the rotary motion that the projectile takes up through rifled barrels. In favorable constellations, the vibrations cancel each other out; in unfavorable cases, the vibrations overlap and amplify, which means that a constant precision shot is not possible. In addition, hardly any barrel is absolutely straight, which leads to deflections when the bullet passes through, which represent vibrations. The storage of the weapon barrel (barrel) as a reaction to the recoil can also stimulate barrel vibrations if the design is unfavorable. This occurs particularly clearly when the recoil is introduced into the shaft through a recoil stud in the vicinity of the bolt head. A moment results from the recoil force and the distance between the initiation of the recoil in the bearing and becomes effective when the projectile begins to move in the barrel. In such constructions, the barrel executes a regular whip movement during the bullet passage, the amplitude of which can be several millimeters. Calibers with a high projectile mass and relatively low projectile velocity (e.g. 9.3 × 62) show measurable height variation as a function of the muzzle velocity solely from the velocity variation of the ammunition within an ammunition lot. In the early 1990s, a well-known German hunting rifle manufacturer withdrew an affected weapon series from the market as a result of a diploma thesis, another series was replaced by a new design that has a very low-torque barrel bearing and is beyond any doubt with regard to shooting precision. As an immediate measure after the dissertation was submitted until the new design was launched, bolt-action rifles in the particularly critical 9.3 × 62 caliber were no longer sold; customers were advised to use a different caliber in the event of complaints regarding the shooting performance.
These connections had already been scientifically investigated and published by Carl Cranz and Sam H. Goldstein, but had been forgotten in the course of time.
- R. Böhm: The German Guns 1939-1945. Edited by FM von Senger and Etterlin . Bechtermünz, Augsburg 2002, ISBN 3-8289-0524-2 , p. 18.
C. Cranz : Textbook of Ballistics. Teubner, Leipzig a. a.
- Volume 1: External ballistics or theory of the movement of the projectile from the muzzle of the weapon to penetration into the target. 1910;
- Volume 2: Internal Ballistics. The movement of the projectile through the barrel and its accompanying phenomenon. 1926;
- Volume 3: Experimental ballistics or teaching of the ballistic measurement and observation methods. 1913;
- Volume 4: Atlas for tables, diagrams and photographic snapshots. 1910.
- Jürgen Gebauer, Egon Krenz (ed.): Marine encyclopedia. 2nd revised edition. Brandenburgisches Verlags-Haus, Berlin 1998, ISBN 3-89488-078-3 , p. 194, p. 296.
- Sam H. Goldstein: barrel vibrations in precision weapons. Online (PDF; 876 kB) .
- Karl Sellier, Beat P. Kneubuehl : Wound ballistics and their ballistic basics. 2nd completely revised and expanded edition. Springer, Berlin a. a. 2001, ISBN 3-540-66604-4 .
- Willi Barthold: Jagdwaffenkunde. VEB Verlag Technik, Berlin 1969, edited edition 1979, pp. 16-25.
- Viktor Schützenhofer: Josef Werndl and his work in: Blätter für Geschichte der Technik 1938, Springer Verlag , ISBN 978-3-7091-2366-9 , p. 52
- P. Sixl: development and use of handguns . In: Association for historical weapons (Hrsg.): Journal for historical weapons . No. 1 . Burdach, Dresden 1897.
- P. Sixl: development and use of handguns . In: Association for historical weapons (Hrsg.): Journal for historical weapons . No. 2 . Burdach, Dresden 1898.
- Archive link ( Memento from August 27, 2010 in the Internet Archive )
- Gebauer, Krenz: Marine Encyclopedia. Brandenburgisches Verlagshaus, 1998, ISBN 3-89488-078-3 , pp. 194, 296.
- Thomas Enke: Fundamentals of weapon and ammunition technology , Walhalla Fachverlag , 2020, ISBN 978-3-8029-6215-8 pp. 133-135
- Uday S Dixit, Seikh Mustafa Kamal, Rajkumar Shufen: Autofrettage Processes: Technology and Modeling , Verlag CRC Press , 2019, ISBN 9780429757983 pp. 15-16 
- Standard NATO-AC225 / D14
- FM von Senger and Etterlin : The German Guns 1939–1945. Bechtermünz, ISBN 3-8289-0524-2 , p. 18.
- Carl Cranz: Investigations into the vibration of the gun barrel. Physical Institute of the Technical University of Stuttgart, November 1898 ( Memento from May 19, 2010 in the Internet Archive )
- Sam H. Goldstein: Swiss weapons magazine. September 2004 part 1 (PDF; 415 kB), part 2 (PDF; 341 kB)