airguns

An air gun, or airgun, is a gun that fires projectiles pneumatically with compressed air or other gases that are pressurized without involving any chemical reactions, in contrast to a firearm, which pressurizes gases chemically by oxidation of combustible propellants that generates propulsive energy by breaking molecular bonds. Both the "long gun" (air rifle) and "handgun" (air pistol) forms typically propel metallic projectiles that are either diabolo-shaped pellets or spherical shots called BBs, though in recent years Minié ball-shaped slugs are gaining more popularity. Certain types of air guns (usually air rifles) may also propel darts (e.g. tranquilizer guns) or arrows (so-called "airbows").
The first air guns were developed as early as the 1500s, and have since been used in hunting, sporting and warfare. There are three different power sources for modern air guns, depending on the design: spring-piston, pneumatic, or bottled compressed gas (most commonly carbon dioxide).

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