Just had an idea I'll have to wait 'til the weekend to see if it is feasible. Heat a tray of bullets to 300 degrees or so. Use the smaller drum of my wet tumbler (BiggDawg). Add some amount of powder (to be determined) and the hot bullets, then tumble for some amount of time (also T.B.D.) The powder will start to coat everything it touches. It will apply too heavily to the first bullets, but the constant motion will move the powder around (hopefully) until all surfaces of all bullets have been coated.