enough with the competing theories of why the gun won't shoot. Regardless of which of you ever wins this discussion, the gun still won't shoot till action is taken. The OP should have the stock bedded or replaced. If that doesn't fix the problem replace the barrel or the rifle. Or...just take it to a top level gunsmith and tell him to make it shoot. I've done that with two rifles and the results were fantastic.
He could be flinching (I probably would, with that rifle), but that wouldn't give repetitive vertical grouping.
And the BOSS is just plain ugly, even if it works great.