Folks in the BPCR world either use angle cut ceramic, or the newest thing, stainless steel rods in their tumblers. The angle cut allows them to get into the corners of the primer pocket. The stainless steel pins are small enough to go through the primer hole and also get into the corners. Roundish grains can't get into a corner.
I use a Thumbler's Tumbler with ceramic. Soon I will be shifting to the stainless as I load some cartridges that my ceramic media gets jammed up in.
Brass that has been tumbled in ceramic media comes out looking better than new.