IMO the so called crud ring with T7 is over emphasized. Swab between shots with a 50/50 blue Windex and 91% alcohol and you'll be fine. Personally I prefer Pyrodex RS.
i never could understand why BH209 gets all the hype about being so clean. I always swab between shots no matter what powder I'm using and even with BH209 there is a lot of fouling in the bore. Is this fouling softer than black powder or other subs fouling?
i keep trying it and have 2 full containers but I almost always get better accuracy with another powder.