GM54-120, I did purchase 2 of the knight/lehigh breech plugs one my .45elite and onefor the .50 LRH that i have been putting together for a while.( I have basically bought it one piece that a time.And as of how I still have not got to shoot.) I had it in a elite syn stock but i have just purchased one of the new shadow gray thumbhole stock that knight is now offering.
In my .50 master hunter and my .45 extreme I have only used the FPJ with the cavity in the end of it with pretty good luck but like you said it was dirty. That is why I was wondering if one of the other factory breech plugs might work better. I had read that the revolution dome plug was suppose to reduce fouling and blowback when useing T7 but after looking at the nipple and flash hole in the one I got I just didnt know.