One of the guys I shoot with bought a custom .308 from a well known Gunsmith who build rifles for members of SWAT teams and some for the Military. when he uses top notch brands of ammo Norma,Black Hills..and a few others he always gets a round that is no less than 2 inches from his group. the barres is not hot,,the action is glass bedded and the Barrel is floated using a McMillan M5 Stock, WHAT IS THE PROBLEM HERE? He bought a vice to mount his rifle, so I know its on and this is at 100 yards. I think his action is shifting some how? Am I wrong?