"The current technique for manufacturing shot pellets is accomplished with the Bliemeister method. This method eliminates the need for a shot tower.
The steps to produce round pellets are:
Molten lead passes through successive screens that are repeatedly agitated.
Lead droplets fall less than one inch into hot water (as opposed to a ten-story drop).
The near-spherical pellets roll down an incline and are sorted by shape.
The nonrounded, rejected shapes are recycled and remelted."
http://projects.nfstc.org/firearms/module05/fir_m05_t05_04.htm"Lead pellets may be plated with copper or nickel before loading. A tough outer coating helps protect the pellets from deformation. This step is reserved for premium-grade ammunition."