Smoothbore in the context of "Recoilless rifle"

A firearm is any type of gun that shoots projectiles using high explosive pressure generated from combustion (deflagration) of chemical propellant, most often black powder in antique firearms and smokeless powder in modern firearms. Small arms is a subset of light firearms that is designed to be readily carried and operated by an individual. The term "firearm" is however variably defined in both technically and legally in different countries (see legal definitions), and can be used colloquially (sometimes incorrectly) to refer to any type of guns.

The first firearms originated in 10th-century Song dynasty China (see gunpowder weapons in the Song dynasty), when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears to make the portable fire lance, which was operable by a single person and was later used effectively as a shock weapon in the siege of De'an in 1132. In the 13th century, fire lance barrels were replaced with metal tubes and transformed into the metal-barreled hand cannon, and the technology gradually spread throughout Eurasia during the 14th century. Older firearms typically used black powder as a propellant, but modern firearms use smokeless powder or other explosive propellants. Most modern firearms (with the notable exception of smoothbore shotguns) have rifled barrels to impart a stabilizing spin to the bullet for improved external ballistics.

A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually disappeared as the use of heavy armour declined, but musket continued as the generic term for smoothbore long guns until the mid-19th century. In turn, this style of musket was retired in the 19th century when rifled muskets (simply called rifles in modern terminology) using the Minié ball (invented by Claude-Étienne Minié in 1849) became common. The development of breech-loading firearms using self-contained cartridges, introduced by Casimir Lefaucheux in 1835, began to make muskets obsolete. The first reliable repeating rifles, the 1860 Henry rifle and its 1866 descendant the Winchester rifle, superseded muskets entirely. Repeating rifles quickly established themselves as the standard for rifle design, ending the era of the musket.

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.

The Leopard 2 is a third generation German main battle tank (MBT). Developed by Krauss-Maffei in the 1970s, the tank entered service in 1979 and replaced the earlier Leopard 1 as the main battle tank of the West German army. Various iterations of the Leopard 2 continue to be operated by the armed forces of Germany, as well as 13 other European countries, and several non-European countries, including Canada, Chile, Indonesia, and Singapore. Some operating countries have licensed the Leopard 2 design for local production and domestic development.

There are two main development tranches of the Leopard 2. The first encompasses tanks produced up to the Leopard 2A4 standard and are characterised by their vertically faced turret armour. The second tranche, from Leopard 2A5 onwards, has an angled, arrow-shaped, turret appliqué armour, together with other improvements. The main armament of all Leopard 2 tanks is a smoothbore 120 mm cannon made by Rheinmetall. This is operated with a digital fire control system, laser rangefinder, and advanced night vision and sighting equipment. The tank is powered by a V12 twin-turbo diesel engine made by MTU Friedrichshafen.

"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.

Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such grooves. The opposite of rifling is smoothbore.

Rifling is measured in twist rate, the distance the rifling takes to complete one full revolution, expressed as a ratio with 1 as its base (e.g., 1:10 inches (25.4 cm)). A shorter distance/lower ratio indicates a faster twist, generating a higher spin rate (and greater projectile stability).

A mortar today is usually a simple, lightweight, man-portable, muzzle-loaded cannon consisting of a smooth-bore (although some models use a rifled barrel) metal tube fixed to a base plate (to spread out the recoil) with a lightweight bipod mount and a sight. Mortars are typically used as indirect fire weapons for close fire support with a variety of ammunition. Historically, mortars were heavy siege artillery. Mortars launch explosive shells (technically called bombs) in high arching ballistic trajectories.