My .308 Montana is light, but its accuracy has been very disappointing. I have to work my tail off to get 1.5 MOA, which is strange for something with match barrel, match trigger, pillar bedding, etc.
Not to strange considering the gun weighs less then 6 lbs it should have some fierce recoil. I would have someone else shoot it and if so send it back to them. BTW your lucky to have model 70's that shoot submoa. They probably weigh 2 lbs or more then the MOntana.