BB guns are a type of air gun designed to shoot projectiles named BBs after the birdshot pellet of approximately the same size. These projectiles are usually spherical but can also be pointed; those are usually used for bird hunting. Modern day BB guns usually have a smoothbore barrel, with a bore diameter and caliber of 0.177 inches (4.5d mm). BB for modern day BB guns are usually steel, plated either with zinc or copper to resist corrosion, and measure 0.171 to 0.173 inches (4.34c mm to 4.39e mm) in diameter. Some manufacturers also still make lead balls of slightly larger diameter and which are generally intended for use in rifled BB gun barrels, as were formerly used in BB guns. Some Asian companies make plastic BBs for recreation.
Airsoft guns are also commonly referred to as BB guns or pellet guns, as they also launch spherical projectiles (typically through a smoothbore barrel). Common airsoft BBs are 6 mm in diameter (0.24i inches), and are generally made of plastic or other non-metallic materials specifically designed to impart low target damage (however, such can still be dangerous if carelessly or improperly used). Airsoft projectiles are often employed for wargames similar to paintball.
While it is often stated that the term BB originated from ball bearing or bullet ball (if it's made of plastic), this is not the case.[1] The original BB guns used the BB-sized lead shot for shotguns, midway between B and BBB size. BB shot was nominally 0.180n inches (4.57u mm), but tended to vary considerably in size due to the high allowable tolerances for shotgun shell use. Around 1900, Daisy, one of the earliest makers of BB guns, changed their BB gun bore diameter to .175r inches (4.45l mm), and began to market precision-made lead shot specifically for their BB guns. They called this air rifle shot , but the BB name was already well established, and everyone continued calling the guns BB guns and the shot BB shot or just BBs .
Since nearly all BBs used today are steel, it is common to find BB guns that use magnets in their loading mechanisms. Since the BB is too hard to be swaged to the bore size, magnets are often used to hold the BB at the rear of the barrel—otherwise, the BB would simply roll out of the barrel if it were held at a downward angle.
