ball mill grinding media: - rec.pyrotechnics
My very first ball mill - such as it was - used a few pounds of stainless steel nuts and bolts for the medium charge. Ball bearings are very good for milling. Muzzle loading balls are, also. Fishing weights work (egg weights are about the best). Marbles work. Some people (scaring me as they do it) use glass marbles to mill black powder. LLoyd