Caliber in the context of "Aircraft cannon"

A shotgun (also known as a scattergun, peppergun, or historically as a fowling piece) is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which discharges numerous small spherical projectiles called shot, or a single solid projectile called a slug. Shotguns are most commonly used as smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting sabot slugs (slug barrels) are also available.

Shotguns come in a wide variety of calibers and gauges ranging from 5.5 mm (.22 inch) to up to 5 cm (2.0 in), though the 12-gauge (18.53 mm or 0.729 in) and 20-gauge (15.63 mm or 0.615 in) bores are by far the most common. Almost all are breechloading, and can be single barreled, double barreled, or in the form of a combination gun. Like rifles, shotguns also come in a range of different action types, both single-shot and repeating. For non-repeating designs, over-and-under and side-by-side break action shotguns are by far the most common variants. Although revolving shotguns do exist, most modern repeating shotguns are either pump action or semi-automatic, and also fully automatic, lever-action, or bolt-action to a lesser extent.

A cannon (plural either cannons or cannon) is a large-caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder during the late 19th century. Cannons vary in gauge, effective range, mobility, rate of fire, angle of fire and firepower; different forms of cannon combine and balance these attributes in varying degrees, depending on their intended use on the battlefield. A cannon is a type of heavy artillery weapon. The word cannon is derived from several languages, in which the original definition can usually be translated as tube, cane, or reed.

The earliest known depiction of cannons may have appeared in Song dynasty China as early as the 12th century; however, solid archaeological and documentary evidence of cannons do not appear until the 13th century. In 1288, Yuan dynasty troops are recorded to have used hand cannons in combat, and the earliest extant cannon bearing a date of production comes from the same period. By the end of the 14th century, cannons were widespread throughout Eurasia.

A gun is a device that propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or cannons), or gas (e.g. light-gas gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Tasers, spearguns and harpoon guns). A large-caliber gun is also called a cannon. Guns were designed as weapons for military use, and then found use in hunting. Now, there are guns, e.g., toy guns, water guns, paintball guns, etc., for many purposes.

The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within a barrel tube (gun barrel), produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing and accelerating it down the length of the tube, imparting sufficient launch velocity to sustain its further travel towards the target once the propelling gas ceases acting upon it after it exits the muzzle. Alternatively, new-concept linear motor weapons may employ an electromagnetic field to achieve acceleration, in which case the barrel may be substituted by guide rails (as in railguns) or wrapped with magnetic coils (as in coilguns).

"Brown Bess" is a nickname of uncertain origin for the British Army's muzzle-loading smoothbore flintlock Land Pattern Musket and its derivatives. The musket design remained in use for over a hundred years with many incremental changes in its design. These versions include the Long Land Pattern, the Short Land Pattern, the India Pattern, the New Land Pattern Musket, and the Sea Service Musket.

The Long Land Pattern musket and its derivatives, all 0.75 inches calibre flintlock muskets, were the standard long guns of the British Empire's land forces from 1722 until 1838, when they were superseded by a percussion cap smoothbore musket. The British Ordnance System converted many flintlocks into the new percussion system known as the Pattern 1839 Musket. A fire in 1841 at the Tower of London destroyed many muskets before they could be converted. Still, the Brown Bess saw service until the middle of the nineteenth century.

A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions (depending on the intended applications), including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter (referred to as "caliber") in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.

Stopping power is the supposed ability of a weapon — typically a ranged weapon such as a firearm — to cause a target (human or animal) to be incapacitated or immobilized. Stopping power contrasts with lethality in that it pertains only to a weapon's ability to make the target cease action, regardless of whether or not death ultimately occurs. Which ammunition cartridges have the greatest stopping power is a much-debated topic.

Stopping power is related to the physical properties and terminal behavior of the projectile (bullet, shot, or slug), the biology of the target, and the wound location, but the issue is complicated and not easily studied. Although higher-caliber ammunitions usually have greater muzzle energy and momentum and thus traditionally been widely associated with higher stopping power, the physics involved are multifactorial, with caliber, muzzle velocity, bullet mass, bullet shape and bullet material all contributing to the ballistics.

A round shot (also called solid shot or simply ball) is a solid spherical projectile without explosive charge, launched from a gun. Its diameter is slightly less than the bore of the barrel from which it is shot. A round shot fired from a large-caliber gun is also called a cannonball.

The cast iron cannonball was introduced by French artillery engineers after 1450; it had the capacity to reduce traditional English castle wall fortifications to rubble. French armories would cast a tubular cannon body in a single piece, and cannonballs took the shape of a sphere initially made from stone material. Advances in gunpowder manufacturing soon led the replacement of stone cannonballs with cast iron ones.

In artillery, a grapeshot is a type of ammunition that consists of a collection of smaller-caliber round shots packed tightly in a canvas bag and separated from the gunpowder charge by a metal wadding, rather than being a single solid projectile. When assembled, the shot resembled a cluster of grapes, hence the name. Grapeshot was used both on land and at sea. On firing, the canvas wrapping disintegrates and the contained balls scatter out from the muzzle, giving a ballistic effect similar to a giant shotgun.

Grapeshot was devastatingly effective against massed infantry at short range and was also used at medium range. Solid shot was used at longer range and canister at shorter. When used in naval warfare, grapeshot served a dual purpose. First, it continued its role as an anti-personnel projectile. However, the effect was diminished due to a large portion of the crew being below decks and the addition of hammock netting in iron brackets intended to slow or stop smaller shot. Second, the shot was cast large enough to cut rigging, destroy spars and blocks, and puncture multiple sails.

The formal definition of large-calibre artillery used by the United Nations Register of Conventional Arms (UNROCA) is "guns, howitzers, artillery pieces, combining the characteristics of a gun, howitzer, mortar, or rocket, capable of engaging surface targets by delivering primarily indirect fire, with a calibre of 76.2 mm (3.00 in) and above". This definition, shared by the Arms Trade Treaty and the Treaty on Conventional Armed Forces in Europe, is updated from an earlier definition in United Nations General Assembly Resolution 46/36L, which set a threshold of 100 mm (3.9 in). Several grammatical changes were made to that latter in 1992 and the threshold was lowered in 2003 to yield the current definition, as endorsed by UN General Assembly Resolution 58/54.

Historically, large-calibre weapons have included bombards and siege guns.