I used a 4-12x40 with an adjustable objective scope (Vortex Diamondback) to shoot a 1 inch group at 100 yards. I think the wind will be more of a problem than your optics.
I also routinely use a 4-16, although I feel the image becomes a little washed out above 12x if you don't have a large enough front objective on the scope. My 4-16 is 42mm objective so the exit pupil is only 2.6 mm in diameter. Very easy to move slightly and see one corner of the image start to darken.