Traditionally ‘BB’ is short for Ball Bearing, though in Airsoft terms a BB is made from plastic instead of metal. Most Airsoft guns fire 6mm BBs, though some fire 8mm BBs. The standard weight for game BBs is .2g, heavier BBs are used in some cases (usually sniper rifles), which travel slightly slower but are more accurate over longer ranges when used with the higher powered sniper rifles.
