Ooh..sorry. Yes indeed. Id consider 18x to be the minimum for this
type of work, and 24x the maximum. Even at 50 yrd..with more
magnification..mirage will be a big issue. And of course so will your
heart beat.

Gunner

My .02 worth. Agreed 18-24 power works well at 50 yards. I disagree that
mirage is a problem. I used to shoot centerfire bench rest with a 44X scope.
The mirage helps you see the wind. Its helpful to be able to read the
condition of the atmosphere out there. Wind flags aren't enough. Warren Page
explains it very well in his book "The Accurate Rifle" in the chapter named
appropriately 'Shooting Through the Swimming Pool'.