I am certainly no expert when it comes to BP shooting. My Traditions Pursuit shoots different when shooting from a clean barrel or fouled. I use the BH209 and if I dont swab my barrel in between shots my shot groups are very close to 1" at 100yds from a fouled barrel. If I swab the barrel in between shots my bullet tends to hit 2" to 3" to the right of my grouping. When I first start shooting at the range with my clean gun, my groups most definitely tighten up the more fouled my barrel gets. I am using the Barnes TEZ bullets also. I dont know if this has any relation to your situation or not, but thought I would mention it. What I have been doing is leaving my barrel fouled during the two week season here in Va. and scrubbing it good after the season is over.