could be like cayugad said, may not like XTP's. But im not exactly sure about that. I'd give some Great plains conicals a try, 385 grains or TC maxi hunters. Just because they shoot great for me, doesnt mean they will for you but its worth a shot. Or it could be flinching. Maybe have a couple friends come over and all of you guys shoot it and see what happens.

What kind of primer you using? If it has a stiff trigger than its more than likely that causing your groups to open up a bit. Give CVA a call and they'll adjust it down for you. 3.5lbs is the max that they will allow. Safety reasons.

Just have to fix one thing at a time, play with new powder charges until you find what it likes.