I really do not know what to tell you.. I have a T/C Black Diamond XR and it shoots about anything I want to shove down the barrel real well. Have you tried to shoot the 250 grain Shockwaves? And are you swabbing between shots? Also the XTP's shoot very well out of my BD. Like I said, if you are working your loads, swabbing, I just do not know what it could be. If you call T/C they will tell you to try the Shockwave.

When you shoot conicals, are you using small powder charges. 80 grains is plenty for them when you shoot conicals. Then again, I do not have the 22" barrel version.