I agree with Gm54-120 you are using the wrong products for BH209 take his advise. I have a tight CVA Optima V2 Nitride rifle, 1:28 twist like your T/C, an can shoot multiple times with 90 gr. BH volume, no swabbing with no problems loading. I shoot a 300gr. XTP in Harvester crushrib sabot, very accurate for me. Did you clean out all the crusty residue in your breech plug formed by BH209? That can/will cause accuracy issues as well.