Firearm

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 both technically and legally in different countries (see legal definitions), and can be used colloquially (sometimes incorrectly) to refer to any type of guns including air 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, but there is little information regarding how this spread occurred. Older firearms typically used black powder as a propellant. Beginning in the 1860s, black powder was gradually replaced by smokeless powder, which is mostly based on nitrocellulose. In contrast to black powder, it produces almost entirely gas upon combustion, earning it the title "smokeless powder." 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. Modern firearms can be described by their caliber (i.e. bore diameter). For handguns and rifles this is given in millimeters or inches (e.g. 7.62mm or .308 in.); in the case of shotguns, gauge or bore (e.g. 12 ga. or .410 bore.). They are also described...