I took a look tonight, ran a dry patch down the bore and it came out with a little colour but nothing like the other night. I coated another patch with Gunzilla CLP and swabbed the bore, will check again.
I never seemed to have the same issue with the centerfires when using Hoppes #9, I will make sure to swab with the CLP for sure moving forward and keep my eyes on things, still new to the BP game.