To me it seems that cleaning the flame channel of the breech plug, is far more important, than cleaning the barrel, whilst using BH209. However, i must admit, i never clean nuthin' when shooting paper.

I did clean the flame channel once in between targets when shooting Blackhorn. That's some crusty stuff. It may have been when I was changing from blackhorn 209 to another powder. I didn't make a note of it unfortunately and I really don't remember when it was.

i'd ditch those w209 primers and use the cci 209 mags with blackhorn

I need to pick some up. Is it an accuracy thing? Because I had no ignition problems.

yes its an accuracy thing. The cci mags have been the most accurate for me. I tried some italian brand primers and accuracy went to being horrible.