So you haven't tried free-floating the barrels on the 77's? In my experience they shoot better floated. I had a 6.5x55 Mark II that was VERY accurate with the barrel floated. Killed a lot of game with it, including one pronghorn at almost 400 yards, then sold it to a friend of Karnis's and have kind of regretted it since.
You can temporary-test a wood-stocked 77 by putting a spacer inside the stock behind the recoil lug. A plastic bread-bag twist-closer usually works great.
