Shooting my ML the other day and was having great groups shooting PRB's and Pyrodex RS in my .50, I use Bore Butter as a patch lube, always have. Cleaned up my bore with NO.13 and started to try a new can T7 FF, accuracy went away instantly. Used loads from 60 to 75 grains in 5 gr increments. Could not find a patch down range and what I did find was burnt almost gone, started to become really hard to seat a PRB within 5 shots. I could shoot 20 rounds before cleaning the barrel with Pyrodex, 5 shots with T7 and I could verily seat a ball?? I'm thinking the sugar based T7 was having adverse effects with the Bore Butter. Anyone else have problems shooting T7 with PRB's