What primer are you using with the BH? May want to try a different primer. When I first tried BH209 out of my Omega I couldn't get good groups either and that was with Winchester muzzleloading primers. I tried Remington STS primers and chazam! I never looked back after that. You may also want to try less powder. I shoot a 350 gr. FPB over 85 gr. of BH209. 85 grains had enought power to kill anything your going to shoot at muzzleloader distances.