I have found if you keep running wet Hoppe's or BH209 solvent down and out the bore they will keep coming out a little dirty. If I run a dry patch down after the first wet one clean up is quicker. Alot of the mess is down by and around the breech plug and if cleaning with the plug in it will keep picking up the fouling down there. After a few patches I pull the breech plug and run the patch all the way through and clean the threads. BH209 solvent to me is no better than Hoppe's. BH209 solvent has a very strong amonia odor so be ready to air the house out after cleaning or clean at the range to keep the Mrs. happy. My last patch on a dry bore is with a lightly coated Montana X-Treme patch.

Barrel heat with BH209 is going to affect your accuracy more than fouling. Carbon build up in the flash channel would be second runner up.

My first few jugs of BH209 I ran one dry patch between shots - just couldn't help it. I asked around and the consensus seemed to be don't swab with Blackhorn. Since I stopped, my shots have gotten more consistent.