I have a 7mm RUM that I pillar bedded into an A2 stock. The bedding job seems pretty neutral with almost no movement when you tighten down the action screws. The barrel is free floated and I don't let it get hot any way. It has a V port muzzle brake from Straight Shot Gunsmithing (308 nate). It has shown a definite tendency towards vertical stringing with 150 gr BT's loaded to magazine length. I haven't chronographed a series of rounds to check my ES yet but at 100 yards groups will be under 0.5" with horizontal spread in the 1's and I shot her at 200 yards the other day. 3 shots into 0.6", again with horizontal spread of around 0.1". All groups shot off sand bags and using a Leupold 6.5-20 SF scope. Ideas?