I have a fixed 4x on my 7x57, a 1.5-5x on my 9.3mm, and a 2-7x on the .30/06. I had a 3-9x at one point, but it spent most of it's time on 3x. I find 3 to 4x a good compromise between field of view for close shots and ease of aiming for long ones. My longest shot to date was 200 yds, with a few more at 150, but the potential is there for 300+, across beaver ponds or meadows. If I'm carrying the open sighted .30-30 I go to places where there's no chance for a long shot.