Depends on what you are trying to do. For quick not so precise loading, corn meal is best. It will compress some, so to get a tight load without critical measuring it is best. For most consistant shot to shot, cream of wheat is best. It does not compress much, so it needs to be measured the same as the powder. The powder and filler should come to nearly the top of the cylinder (maybe 1/8" below), so when the ball is compressed it just clears the top of the cylinder, giving the shortest "jump" to the barrel. Then cover the ball with a lube. Crisco, a mixture of bees wax and synthetic motor oil, wonder lube or something. 25 grains is plenty for target and plinking. A full charge of powder is never as accurate. I would lean more toward 20 or less, then make up the difference with the preferred filler. Hope this helps, Jim/OH