I have always tried to be as accurate as possible in every way about hunting. When I install a scope to a rifle, I first put the rifle in a stable and straight position, and then 20 or 30 feet away I put a level so I have an horizontal reference, and behind it I put a plummet with a black string attached for a vertical line of reference. As shown in picture. And then get the scope straight with the vertical and horizontal line. Dont know if I should do this with the minimum or maximum magnification in the scope to make it more precise??? Thanks for the comments.