RE: Hmmm.
I also never used fillers but now I'm curious. I may give it a try. One other question - When I'm hunting, I carry a couple of speed loaders with me. I'm not sure it would be a good idea to add filler to the speed loaders, unless I put enough filler into it between the powder and bullet to avoid 'mixing' while walking.
I may just try filling one with my powder charge, add filler and bullet then shake the crap out of it and see how much powder/filler mix I get.