been using my tumbler to coat pc bullets for a while. First with air soft bbs. then I found that #4 cast buckshot worked a bit better. Gets old picking the bullets out of the shot though so I tried just dumping the bullets in the tumbler with nothing but pc. Worked just as good as the other two methods. Don't know if the same would be if I was using a larger bullet though but the 9s turned out just fine and all I have to do is dump them on a screen to get the excess pc powder out and then dump them on the tray with non stick Reynolds wrap.