The Round Ball calculator allows you to calculate a BC value based on the
Ball diameter and weight. To use the feature enter your Ball Diameter
and Weight then click Calculate. To export the value to the main window
click the Export Button.
If you are casting your own balls be sure to eliminate the sprue's as much
as possible. You want to remove them but not file to the point of making
the ball become out of round. I have heard of people going as far as polishing
the balls in their tumbler then weighing and sizing the resulting balls. Then
matching balls with differing patch thicknesses.
I have never tried this myself.