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Cannon

From Academic Kids

For other uses, see Cannon (disambiguation).
A small cast-iron cannon on a carriage
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A small cast-iron cannon on a carriage

A cannon is any large tubular firearm designed to fire a heavy projectile over a considerable distance. The term can apply to a modern day rifled machine gun with a calibre of 20 mm or more (see autocannon).

Cannon also refers to a large, smooth-bored, muzzle-loading gun used before the advent of breech-loading, rifled guns firing explosive shells.

"Cannon" derives from the Latin canna (a tube). Bombard was early used for "cannon", but from the early 15th century came to refer only to the largest weapons. "Cannon" can serve both as the singular and plural of the noun.

Contents

History

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Firing of a naval 18-pounder gun

The oldest evidence for the use of cannon is a relief carved by Buddhist monks in China in 1128, where a cannon is portrayed among other weapons of war. In the West, the use of cannon was first recorded in the battles of the early 14th century, for instance, at the siege of Metz in 1324, and by the English against the Scots in 1327. The earliest listing of firearms in an army inventory is in 1326. The new weapon's popularity is indicated by cannon being regarded "as common and familiar as any weapon" by 1350. The first cannon were of two types, small guns of cast bronze or larger, banded wrought iron cannon. Developments in gunpowder in the 1400s helped speed the military adoption of cannon. The actual effectiveness of these early weapons is not clear; battle reports of the time tend to exaggerate. However, it is undeniable that regardless of their (usually feeble) physical impact, early cannons, with their noise, smoke, and flames, had a terrifying psychological impact on horses or soldiers who had never encountered the weapons before.

Early cannon did not always fire spherical projectiles. For smaller cannon, arrow-like rounds were used in the 14th century, sometimes with brass fin-stabilisers or inflammable heads. Initially, round shot was made of iron but was soon replaced by stone balls, particularly for larger pieces, due to the cost of metals in the 14th and 15th centuries. The round shot were sometimes covered in lead to reduce windage. For anti-personnel use, massed lead pellets were quickly adopted, but in extremis any small stones, nails, or iron scraps would be used as "hailshot".

The introduction of wheeled carriages for cannon did not occur until the 15th century. Prior to then the weapons were mounted on sturdy wooden frames. The largest siege bombards would be strapped down to large timber baulks on earthwork platforms and aimed either with the initial platform or by hammering wedges under the front. Timber props supporting thick wooden planks were positioned to absorb the recoil.

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A Rodman cannon—a successor to the similarly bottle-shaped Dahlgren cannon

In the 16th century the "Great Guns" were classified according to size, with such names as "cannon royal" (see Tsar Cannon), "demi-cannon", "culverin", "demi-culverin", "falcon", "falconer", "minion" etc., but by the 18th century they were classified by the weight of the round shot that they fired. Thus the demi-cannon was described as a 32-pounder (15 kg). Smaller guns included the 18-pound (8 kg) culverin, 12-pounders (5 kg), 9 pounders (4 kg) and 6-pounders (3 kg). The gun barrel was mounted on a wheeled carriage balanced on two "trunnions", the short metal projections on either side of the barrel invented by an unknown Dutchman. The angle of elevation could be altered by moving a wooden wedge under the rear end of the gun. Shotguns were developed as essentially small cannons, having been first named in Kentucky in the 18th Century; their size, expressed in gauge, is expressed in the fraction of a pound that a round shot of a diameter equal to their barrel bore diameter would be. Hence, a 12 gauge shotgun has a bore that is equivalent in diameter to a round shot of lead weighing one-twelth of a pound; a 20 gauge shotgun has a bore equivalent in diameter to a round shot of lead weighing one-twentieth of a pound, and so forth similarly sizing for 16 gauge and 10 gauge shotguns. The choice of weight, instead of diameter, enabled the fabrication of accurately sized round shot that would accurately fit in the bore of a shotgun or a cannon, through easily measuring a pound of lead against a standard brass weight weighing exactly a pound by using a balance scale, and subdividing the mass of lead down in equal portions for shotguns with a knife before melting the shot into molds, or, similarly, scaling up in equal portions for cannons. The need for a micrometer or other accurate linear measurement tool, for sizing round shot diameter, was eliminated in both instances.

The early big guns were built up from strips of wrought iron, heated until they glowed yellow, and then hammered together to weld them and form the barrel. Rings of iron were forced over the barrel to reinforce it. Smaller guns were cast in brass or bronze, using techniques used for centuries to produce statues. In the 16th century the Dutch developed cast iron cannon. In addition to the obvious implications for land-based artillery, the lighter weight of cast-iron cannon rendered shipboard artillery far more efficient and cost-effective. Cast-iron technology spread to England in 1543, where it grew to become a key element in the British rise to naval supremacy.

In the 18th and early 19th centuries, cannon occupied several roles. On the battlefield they were like modern-day machine guns, used to "thin out" an advancing group of the enemy. In a siege, larger cannon and mortars were used more like conventional artillery or medieval siege weapons, to knock holes in the defences.

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Cast-iron muzzle-loading ship's cannon aboard the Grand Turk

The development of the smooth bore muzzle-loaded cannon culminated in the inventions of John A. Dahlgren, the admiral who designed the heavy, cast-iron cannon fired from Union ships in the American Civil War. In 1862 John Gilleland invented a double barrelled cannon, which turned out to be a spectacular failure. The military use of cannon declined in the mid-19th century as fabrication technology improved enough to enable the rifling of gun barrels (which in turn required the introduction of breech loading, followed by a brief return to muzzle-loading) and the use of the far more destructive explosive shells.

During the nineteenth century, artillery technology advanced at a very rapid rate, ensuring that by the beginning of the twentieth century, modern armies in Europe, America, and Japan were equipped with lethally accurate cannons. Artillery came to dominate the First World War, with approximately 7 million of the estimated 10 million worldwide casualties being caused by artillery shells. Artillery forced armies to construct elaborate trench systems, which became the enduring image of the war. During the Second World War, artillery became less important as battles had become highly mobilised, with bomber aircraft taking over the role of long-range cannons. Cannons in fortified positions, such as the Maginot Line and the Atlantic Wall, were increasingly unable to protect areas from infantry and tank attacks. The German "Big Bertha" guns, capable of firing shells from Occupied France across the English Channel, were technologically unsuitable as each shell wore away 25 mm of the cannon's rifling. The High-pressure gun, designed by German engineers to bombard London, was a spectacular failure.

In cases of emergency, ersatz cannon have been fashioned from objects as diverse as sewer pipes and hollow tree trunks, anecdotally even from alligator carcasses, as described in the historical ballad, The Battle of New Orleans.

Projectiles fired from cannon

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Cannon_diagram.PNG
Essential parts of a cannon: 1. the projectile, or cannonball 2. gunpowder 3. hole in which the fuse is inserted
Round shot 
A solid projectile made, in early times, from dressed stone but, by the 17th century, from iron. The most accurate projectile that could be fired by a smooth-bore cannon, used to batter the wooden hulls of opposing ships, forts, or fixed emplacements, and as a long-range anti-personnel weapon.
Chain shot or bar shot 
Two sub-calibre round shot (a good deal smaller than the bore of the barrel) linked by a length of chain or a solid bar, and used to slash through the rigging and sails of an enemy ship so that it could no longer manoeuvre. Inaccurate and only used at close range.
Canister shot (or case shot
An anti-personnel weapon which included several small round shot or lead musket bullets in a metal can, which broke up when fired, scattering the shot throughout the enemy personnel, like a large shotgun.
Shell 
An anti-personnel weapon, similar to canister shot, but with a can that was much more robust and which also contained a fused explosive charge, trimmed to explode above the heads of the enemy, spreading shot and can fragments in the form of shrapnel over the enemy. First used in the 16th century as a siege weapon fired from mortars, and later as a battlefield weapon.
Grapeshot 
An anti-personnel weapon, similar to canister shot, but with the shot being contained in a canvas bag, and generally of a smaller calibre.
The large amounts of gunpowder make for a smoky mess. Operators hope for a calm day so they can continue to see their target.
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The large amounts of gunpowder make for a smoky mess. Operators hope for a calm day so they can continue to see their target.

Modern cannons

A modern artillery piece is generally referred to either as a "gun", or by the name of its specific type, such as a Howitzer.

Since World War II the term cannon is used to refer to a gun of around 20 mm to 40 mm calibre, typically with an automatic loading action capable of firing explosive ammunition, an auto-cannon.

The minimum calibre of a cannon, 20 mm, has been a de facto standard since WWII, when heavy machine guns of 12.7 mm (0.5") and 13.2 mm calibre were used side by side with 20 mm and larger guns, the latter using explosive ammunition, e.g., RAF fighters with 20 mm Hispano cannon and Luftwaffe with 20 mm and 30 mm cannon.

Most nations use these modern (auto-)cannons on their lighter vehicles. Typical of the type is the 25 mm 'Bushmaster' cannon mounted on the LAV and Bradley armoured vehicles.

See also

Patents

he:תותח nl:Kanon zh:加农炮

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