Had a chance to shoot this weekend and stirred up some confusion. I recently mounted a new scope on a rifle I've had for a while. Shot two 100 yard groups to get it zeroed. It shot very well under moa. I moved out to 200 and the group drifted right about 3 inches. 500 right over 16 inches. I spent alot of time shimming to get the scope lined up with the bore axis. Scratching my head at it really. No wind was present. When I adjusted to correct windage it would move impact inconsistently to the left. It's a Nightforce nxs scope. Any thoughts?