I have been getting the same results with my screened powder, it burns cleaner also than my Goex and beats it gr for gr in velocity not by much but 50/75 fps. I do weigh every load and compress it the same. With a blow tube I can shoot 20 straight from my 45/70, and by then am tired and finished anyhow.
PS. I haven't tried any charcoal other than willow so have no knowledge in that area