BP again

Hello! I'm trying to make a BP, but no success yet. Traditional mix 75/15/10, added 2% of dextrine (for future granulating). All components fine pre-milled. Mixed 2 hours in the ball mill with lead balls. And it not fires. It can burn, producing sparkles, but only with the lighter. Burning immediately stops when the fire source removed. Leaves lot of hard black residues (I don not know what is it, melted sulfur with charcoal maybe). So. Is the "corning" or "granulating" step is necessary? Or may be the components not dryed well? Or may be I should dry the mixed powder? How could I tell if the powder is not dry? It is not lumping, but not too much dusting either.