Lance,
Did you know that the "BB" in "BB gun" stands for "ball bearing"? ~ Sear

S, that's not completely accurate.
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 0.180 inches (4.57 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 .175 inches (4.45 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".

http://en.wikipedia.org/wiki/BB_gun
http://www.pyramydair.com/site/articles/bb-history/