Without wishing to sound 'smart', stick to published data that shows pressure levels suitable to your gun and don't worry about anything beyond the accuracy factor with slugs or the patterns with shot, but DO follow the whole recipe listed. Asumptions can get you into trouble quickly .. well, some anyway. That's why you want to go w/published data. Still, even there a misprint is always possible, so compare with other data and if it seems out of sync then consider it suspect and look elsewhere. Just some thots.