I have a 1000 yard bench gun in 243 win. Scope is Sightron 6x24x42 with 52 moa. Base is Ken Farrell 20 moa. I can't get a zero at 300 yards it still 7" high when out of adjustment. I have this same setup on 2 other guns and can zero at 100 yards. Anyone have any ideas as to what could be the issue.