Maybe that's the problem.. its new and stainless. Sometimes those stainless take longer to break in. Sounds like a great rifle you have there and a good set up. I shoot the 240 & 300 grain XTP's with Knight or MMP sabots, or Barnes Expanders, but they are expensive. I have also been shooting some Shockwaves and they seem to be shooting well, although I have not got back to long distance with it yet.

I have been shooting a new stainless barrel on my Renegade and I finally took and scrubbed the bore with some J-B Bore Paste because it was eating all the cleaning patches it was so ruff..

Knight will tell you to shoot 100 grains of Pyrodex and Knight Red Hot Sabots. Those I think are made by Barnes and again, they are expensive to shoot...

Good luck with the rifle. Keep us posted.