Ammo

Ammo, short for ammunition, refers to the consumable items used in firearms and other devices to deliver a projectile and propel it. In the most common form for firearms, ammunition consists of a cartridge: a case that holds a primer, a propellant charge, and a projectile, sealed at the rear by the primer. The front end contains the bullet. In a shotgun shell the components include a hull, a powder charge, a wad, and projectiles such as lead pellets or a slug.

Cartridges are categorized by caliber or gauge and by the type of projectile. Centerfire cartridges have a primer in the center of the base; rimfire cartridges have the primer around the rim. Rifle and pistol rounds use metal cases with varying bullet shapes and jacket configurations, while shotgun shells are measured in gauges and can be loaded with different shot sizes or slugs. Other forms include airgun pellets and BBs used in non-firearm devices.

Common terms include caliber (the inside diameter of the bore or projectile diameter), gauge (for shotguns), bullet (the projectile in a cartridge), cartridge case, primer, and propellant. The distinction between bullets and cartridges is often confused; the term bullet refers to the projectile, while cartridge refers to the assembled unit.

Historical development began with black powder firearms and gradually transitioned to smokeless powder in the late 19th century, enabling higher velocity and reliability. Modern cartridge design emphasizes safety, ballistic performance, and standardization across weapon platforms.

Use and regulation of ammunition vary by country and jurisdiction. Safe handling, proper storage, transport requirements, and licensed sales and reloading activities are common legal considerations. Due to potential hazards, ammunition should be used only in compliant, appropriate firearms and in accordance with all laws and safety practices.