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43-408: The tank had an advanced design for its time, being the first tank produced to feature an all-welded construction and using periscopes for visibility rather than view slits. It was armed with a turret mounted Bofors 37 mm anti-tank gun L/45 ( 37 mm kanon fm/32 ) and two Browning M1917 machine guns ( 6.5 mm kulspruta m/14-29 ), one coaxial mounted in the turret and one flexible mounted in the hull, and

86-433: A flying projectile . Chambering a gun is the process of loading a cartridge into the gun's chamber, either manually as in single loading , or via operating the weapon's own action as in pump action , lever action , bolt action or self-loading actions. In the case of an air gun , a pellet (or slug) itself has no casing to be retained and will be entirely inserted into the chamber (often called "seating" or "loading"

129-399: A particular caliber or model of cartridge. The bore is the hollow internal lumen of the barrel, and takes up a vast majority portion of the barrel length. It is the part of the barrel where the projectile (bullet, shot, or slug) is located prior to firing and where it gains speed and kinetic energy during the firing process. The projectile's status of motion while travelling down

172-461: A tapered constriction called choke to shape the scatter pattern for better range and accuracy. Chokes are implemented as either interchangeable screw-in chokes for particular applications, or as fixed permanent chokes integral to the barrel. 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

215-400: Is a crucial part of gun -type weapons such as small firearms , artillery pieces , and air guns . It is the straight shooting tube, usually made of rigid high-strength metal , through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end ( muzzle ) at a high velocity. The hollow interior of the barrel is called the bore , and

258-414: 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

301-564: The Dutch M39 Pantserwagen and the Polish 7TP to name a few. As the armor of tanks was increased during World War II the gun very quickly became obsolete as an anti-tank gun but was still used effectively as an infantry support gun for the entirety of the war, and well into the Cold War . This was due to its high fire rate, great mobility and effective high explosive shells. The gun

344-618: The Wehrmacht consisted mainly of light Panzer I and Panzer II tanks, which were vulnerable to the Bofors gun. Early models of the Panzer III and Panzer IV could also be penetrated at ranges up to 500 m. After Poland was occupied, most of the guns fell into the hands of the German and Soviet armies. The weapon was proven obsolete by 1941 during Operation Barbarossa . Even though only one Bofors AT-gun

387-483: The diameter of the bore is called its caliber , usually measured in inches or millimetres . 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

430-407: The propellant is ignited and deflagrates , generating high-pressure gas expansion within the cartridge case. However, the chamber (closed from behind by the bolt) restrains the cartridge case (or shell for shotguns) from moving, allowing the bullet (or shot / slug in shotguns) to separate cleanly from the casing and be propelled forward along the barrel to exit out of the front (muzzle) end as

473-589: The structural strength and rigidity and increase the overall specific strength . Fluting will also increase the surface-to-volume ratio and make the barrel more efficient to cool after firing, though the reduced material mass also means the barrel will heat up easily during firing. 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 carbon fiber sleeves, but there are proprietary examples such as

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516-517: The 1930s of which several bought licences to produce it themselves. The gun was used in several conflicts but most of its fame comes from its use in the Spanish Civil War and the Winter War where it was used very successfully against light tanks and armored cars among other targets. Beyond its use as an infantry gun it was also used as the main armament in several armored cars and tanks such as

559-479: The English name. Gun barrels are usually made of some type of metal or metal alloy . However, during the late Tang dynasty , Chinese inventors discovered gunpowder , and used bamboo , which has a strong, naturally tubular stalk and is cheaper to obtain and process, as the first barrels in gunpowder projectile weapons such as fire lances . The Chinese were also the first to master cast-iron cannon barrels, and used

602-476: The Netherlands and Poland. The barrel was of monobloc type, with semi-automatic vertical sliding breech block and small muzzle brake . It was mounted on a split trail carriage which had suspension and metal wheels with rubber tires. To give the crew some protection from firearms and shell fragments, the gun was equipped with a 5 mm thick shield, with a folding lower plate. The Bofors gun saw combat for

645-517: The Teludyne Tech Straitjacket. They are seldom used outside sports and competition shooting . A barrel can be fixed to the receiver using action threads or rivets. Depending on construction different gun barrels can be used: The chamber is the cavity at the back end of a breech-loading gun 's barrel where the cartridge is inserted in position ready to be fired. In most firearms ( rifles , shotguns , machine guns and pistols ),

688-652: The United States 37 mm Gun M3 ). There were many different ammunition types available for the Bofors 37 mm at gun. It could fire all common types of ammunition and some rare types such as APDS and white phosphorus incendiary . – – – – – – – – 40 mm at 400 m 35 mm at 600 m 32 mm at 800 m 29 mm at 1000 m – – – – 30 mm at 400 m 27 mm at 600 m 24 mm at 800 m 22 mm at 1000 m – – – – - - 30 mm at 900 m – – – - - - - - - - - - Gun barrel A gun barrel

731-505: The barrel (i.e. the external ballistics ). Any gun without riflings in the bore is called a smoothbore gun. 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

774-454: The barrel too weak to withstand the pressures of firing, causing it to fail and fragment explosively. A gun barrel must be able to hold in the expanding gas produced by the propellants to ensure that optimum muzzle velocity is attained by the projectile as it is being pushed out. If the barrel material cannot cope with the pressure within the bore, the barrel itself might suffer catastrophic failure and explode, which will not only destroy

817-455: The bore is referred to as its internal ballistics . Most modern firearms (except muskets , shotguns, most tank guns , and some artillery pieces ) and air guns (except some BB guns ) have helical grooves called riflings machined into the bore wall. When shooting, a rifled bore imparts spin to the projectile about its longitudinal axis, which gyroscopically stabilizes the projectile's flight attitude and trajectory after its exit from

860-459: The cartridge. Flash suppressors or muzzle shrouds can be attached to the muzzle of the weapon to either diminish or conceal the flash. The rapid expansion of propellant gases at the muzzle during firing also produce a powerful shockwave known as a muzzle blast . The audible component of this blast, also known as a muzzle report , is the loud "bang" sound of gunfire that can easily exceed 140 decibels and cause permanent hearing loss to

903-413: 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 bolt , making the front direction the path of least resistance during firing. When the cartridge's primer is struck by the firing pin ,

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946-419: The chamber is an integral part of the barrel, often made by simply reaming the rear bore of a barrel blank, with a single chamber within a single barrel. In revolvers , the chamber is a component of the gun's cylinder and completely separate from the barrel, with a single cylinder having multiple chambers that are rotated in turns into alignment with the barrel in anticipation of being fired. Structurally,

989-433: The collection of the new Swedish Tank Museum Arsenalen , were it have remained. Example list (incomplete) Background: History of the tank , Tank classification , interwar period Bofors 37 mm anti-tank gun The Bofors 37 mm anti-tank gun was an anti-tank gun designed by Swedish manufacturer Bofors in the early 1930s originally for Swedish use. It was exported to several countries during

1032-422: The combustion of gunpowder or salt water when used on naval vessels. Early firearms were muzzleloaders , with the gunpowder and then the shot loaded from the front end (muzzle) of the barrel, and were capable of only a low rate of fire due to the cumbersome loading process. The later-invented breech-loading designs provided a higher rate of fire, but early breechloaders lacked an effective way of sealing

1075-480: The escaping gases that leaked from the back end (breech) of the barrel, reducing the available muzzle velocity . During the 19th century, effective breechblocks were invented that sealed a breechloader against the escape of propellant gases. 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

1118-580: The first time in Spanish Civil War , where it could easily pierce the armor of contemporary light tanks. The Polish guns were actively used during the German and Soviet invasion of Poland in 1939. Volhynian Cavalry Brigade equipped with the Bofors 37 mm antitank gun beat the German Panzer Divisions in one of the first battles of the invasion; the Battle of Mokra . At that time, the armored forces of

1161-412: The greatest thermomechanical stress and therefore suffers wear the fastest. Throat erosion is often the main determining factor of a gun's barrel life. The muzzle is the front end of a barrel from which the projectile will exit. 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

1204-403: The gun but also present a life-threatening danger to people nearby. Modern small arms barrels are made of carbon steel or stainless steel materials known and tested to withstand the pressures involved. Artillery pieces are made by various techniques providing reliably sufficient strength. Fluting is the removal of material from a cylindrical surface, usually creating rounded grooves, for

1247-791: The gun was found to be ineffective against the T-34 and KV and was relegated to an infantry support role. The gun was used to equip the British forces in North Africa , where it made up for the lack of the QF 2-pounder anti-tank guns after the Fall of France . It was often carried portee on the back of a vehicle. Bofors guns were also employed in World War II by Germany, the Netherlands, Romania, Yugoslavia and USSR, but there are no detailed reports of their use. When it

1290-424: 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

1333-608: The move) depending on the travel surface (road/terrain). A mild steel prototype with a wooden mockup turret was ordered in 1931 (designated stridsvagn fm/31 : fm = försöksmodell , "trial model") along the three L-10 (strv m/31) and delivered to the Swedish Army for trials in 1935. One L-10 (strv m/31) has been preserved. The vehicles was exhibited at the Swedish Armour Museum in Axvall between 1969 and 2007, then on being moved to

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1376-468: The much improved Landsverk L-60 ( strv m/38 ). When World War II broke out, they were dug in as static bunkers due to a lack of spare parts, as many key parts were produced abroad. The L-10 had a variant, known as the L-30, which featured deployable wheel propulsion in addition to its tracks, the idea being that wheeled and tracked propulsion could be quickly interchanged (in less than a minute, even while on

1419-412: 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

1462-416: The pellet, rather than "chambering" it) before a mechanically pressurized gas is released behind the pellet and propels it forward, meaning that an air gun's chamber is functionally equivalent to the freebore portion of a firearm barrel. 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

1505-481: 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 cylinder of a revolver or the bolt of a bolt-action rifle . Most flutings on rifle barrels and revolver cylinders are straight, though helical flutings can be seen on rifle bolts and occasionally also rifle barrels. While the main purpose of fluting is just to reduce weight and improve portability, when adequately done it can retain

1548-411: 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 smooth bore barrels firing multiple sub-projectiles (such as shotgun shot), the bore at the muzzle end might have

1591-423: The shooter and bystanders. The non-audible component of the blast is an infrasonic overpressure wave that can cause damage to nearby fragile objects. Accessory devices such as muzzle brakes and muzzle boosters can be used to redirect muzzle blast in order to counter the recoil -induced muzzle rise or to assist the gas operation of the gun, and suppressors (and even muzzle shrouds) can be used to reduce

1634-403: The technology to make the earliest infantry firearms — the hand cannons . Early European guns were made of wrought iron , usually with several strengthening bands of the metal wrapped around circular wrought iron rings and then welded into a hollow cylinder. Bronze and brass were favoured by gunsmiths , largely because of their ease of casting and their resistance to the corrosive effects of

1677-567: Was equipped with 8–24 mm (0.31 in – 0.94 in) of armour. Development of the L-10 started in 1930 as part of a competition set up by the Royal Swedish Army Materiel Administration (KAF) for the next generation of Swedish tanks. Landsverk competed against designs from AB Bofors (Krupp) and Morgårdshammar AB, evaluation being conducted in the fall the same year. Landsverks designs came out on top and Landsverk

1720-624: Was in action in the invasion of Denmark , it damaged two tanks, and shot the tracks off another tank, before its crew were either wounded or killed by a German tank destroyer which drove over the gun. The gun is now at the Tøjhusmuseet in Copenhagen. During the Winter War , the Finnish guns were successfully used against Soviet tanks such as T-26 , T-28 and BT . However, in the Continuation War

1763-493: Was initially designed by Swedish manufacturer Bofors, mainly for export purposes. It was likely derived from Rheinmetall's 3,7-cm Tak, the predecessor of 3.7 cm Pak 36 . The first prototype was built in 1932; the development process continued until 1934. The Netherlands were the first to purchase the gun (order for 12 pieces was placed in 1935) and were followed by many other countries. Licensed copies were produced in Denmark, Finland,

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1806-461: Was introduced, the Bofors 37 mm anti-tank gun was an effective weapon, able to deal with contemporary tanks. Its performance, light weight and high rate of fire made it a popular anti-tank weapon in the pre-war Europe. Introduction of better armored tanks early in World War II , however, made the gun obsolete (as with other similarly performing weapons such as the German 3.7 cm Pak 36 and

1849-634: Was selected as contractor in January 1931. After further in-depth evaluation of Landsverks designs, KAF ordered three L-10 test vehicles from Landsverk in October 1931, along one Landsverk L-30 trial vehicle (essentially an L-10 with deployable wheels). The three L-10 vehicles were built in 1933 and delivered to the Swedish Army in 1935. Armour was delivered by Bofors . Despite being highly advanced for their time, they often broke down when not handled properly, and lessons learned from their trials were incorporated into

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