It's obvious that different makes of BP leave different nastiness behind after shooting? I guess it depends on source, purity, ratio, heat generated, pressure, etc... I see where some comment on the various makes and relative dirtiness of the powders. In your experiences, anecdotal or scientific, which powder in which granulation is dirtiest, cleanest etc... This should cover powders currently available. I know of Goex, KIK, Pennsylvania, Graf, Swiss, and Schutzen. If there are others to consider say so. Thanks for the discussion. 10 ga.