Until last year, I'd never killed a big game critter with the scope set on anything higher than 6X (if available). Last year in WY hunting pronghorns, I set the scope at 10X as an experiment. I came home with 3 pronghorns, one taken at 256yds and the other two at 120yds or less. I could easily see myself with a fixed 10X on an open country rifle and a fixed 6X for other places/general purpose big game hunting.