CaliberIn guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matches that specification. It is measured in inches or in millimeters. In the United States it is expressed in hundredths of an inch; in the United Kingdom in thousandths; and elsewhere in millimeters. For example, a US "45 caliber" firearm has a barrel diameter of roughly .
9×19mm ParabellumThe 9×19mm Parabellum (also known as the 9mm Parabellum or the 9mm Luger or simply as the 9mm) is a rimless, tapered firearms cartridge. Originally designed by Austrian firearm designer Georg Luger in 1901, it is widely considered the most popular handgun and submachine gun cartridge due to its low cost and extensive availability. Since the cartridge was designed for the Luger semi-automatic pistol, it has been given the designation of 9mm Luger by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) and the Commission internationale permanente pour l'épreuve des armes à feu portatives (CIP).
HandgunA handgun is a firearm designed to be usable with only one hand. It is distinguished from a long gun (i.e. rifle, shotgun, submachine gun, or machine gun) which needs to be held by both hands and braced against the shoulder. The two most common types of handguns are revolvers and semi-automatic pistols, although other types such as derringers and machine pistols also see infrequent usage. Before commercial mass production, handguns were often considered a badge of office—comparable to a ceremonial sword—as they had limited utility and were more expensive than the long guns of the era.
HandloadingHandloading, or reloading, is the practice of making firearm cartridges by assembling the individual components (case, primer, propellant, and projectile), rather than purchasing mass-assembled, factory-loaded ammunition. (It should not be confused with the reloading of a firearm with cartridges, such as by swapping magazines or using a speedloader.) The term handloading is the more general term, and refers generically to the manual assembly of ammunition. Reloading refers more specifically to handloading using previously fired cases and shells.
ShotgunA 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.
RevolverA revolver is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing. Because most revolver models hold up to six cartridges, before needing to be reloaded, revolvers are commonly called six shooters. Before firing, cocking the revolver's hammer partially rotates the cylinder, indexing one of the cylinder chambers into alignment with the barrel, allowing the bullet to be fired through the bore.
Cartridge (firearms)A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile (bullet, shot, or slug), a propellant substance (usually either smokeless powder or black powder) and an ignition device (primer) within a metallic, paper, or plastic case that is precisely made to fit within the barrel chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is often informally used to refer to a complete cartridge, the correct usage only refers to the projectile.
FirearmA firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions). The first firearms originated in 10th-century China, when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears to make the portable fire lance, operable by a single person, which was later used effectively as a shock weapon in the siege of De'an in 1132.