Again check the scope and mounts. If not that it could be that you have not yet come across that "ideal" factory ammo load.

I helped a guy set up a Browning in 30.06 Spr. He had bought 11 (yes 11) boxes of different factory loads for us to test. We found 4 that grouped really good. We had 3 that were absolutely "MOA dogs" and the others were just OK. One was a legitimate sub 1 MOA shooter. That is the one he selected and he headed back to gather up as many boxes of that lot that he could afford.