As stated above a baffle & consistent technique helps a good bit . Ball powders are the most consistent when you're dispensing by volume , next would be short grained extruded like Vihtavouri powders , long grain extruded & larger flake powders are the hardest to get consistent drops with . Best to set measure to throw just short of your desired weight & finish off with a trickler . Like scales a good powder dispenser aint cheap . Consider that benchrest rifle shooters use thrown charges & you won't find their loads in a manual either , some are eyebrow raising . Most use Harrell powder measures that are extremely precise with selected propellants , but they are costly .