Two suggestions, try some flat based bullets. Some rifles just don't like boattails. I had a .222 that shot FB bullets into 1/2" or less, but the smallest group I ever got with BT's was 1 1/4". Second be very carefull how you rest the forend when shooting. Mark the forend with a piece of tape so you can return it to the same place on the bags for each shot, and by all means try different places to possibly find a sweet spot.