Shot is a collective term for small balls or pellets, often made of lead. These were the original projectiles for shotguns and are still fired primarily from shotguns, although shot shells are available in many pistol calibers in a configuration called "bird shot" or "rat-shot". Lead shot is also used for a variety of other purposes such as filling cavities with dense material for weight/balance. Some versions may be plated with other metals. Lead shot was originally made by pouring molten lead through screens into water, forming what was known as "swan shot", and, later, more economically mass-produced at higher quality using a shot tower. The Bliemeister method has supplanted the shot tower method since the early 1960s.