Cannon balls were made of iron which has a density of 7.87 g/cc (0.284 lb per cubic in).
Standard size of cannon balls were 4, 6, 9, 12, 18, 24, 32 and 42 pounds (lbs)
If a cannon ball weighs X lbs, then its volume is
volume in cc =
= (X lb)* (16 oz/lb)* (28.35 g/oz) / (7.87 g/cc)
diameter of the shot in inches =
= 2 * (((volume) * 3 / (4 * PI()))^(0.333)) / 2.54
If the diameter of a cannon bore was Y inches then the weight of its iron shot is
volume in cc =
= (4 / 3) * PI() * (((Y/2)*2.54)^3)
weight in lbs =
= (volume in cc) * 7.87 / (16 * 28.35)
