You can pretty much go with any optics that you would mount on a decent rimfire rifle, just make sure to use taller rings. But that being said, it was important to me to keep the tactical look of the gun.
After a whole lot of looking, I settled on the Millett DMS 1-4x 28mm. It is designed primarily for use on an AR and the manufacturer claims that is is suitable for use at ranges from 5m out to 400m. It is a combination CQB sight/4x scope... I think it will be decent both for blasting gophers and some target shooting at the range.
I know a few members here have bought them and everyone seems to be very happy so far. I originally bought Millett tall tactical rings, but ended up buying a Burris PEPR base to be able to mount the scope/sight a little further ahead.
1-4x 28mm, illuminated "dot in a donut" reticle (1 MOA dot inside of an 18 MOA circle), and adjustible illumination. The parallax is factory set for 100m; but with the donut-dot system, the manufacturer claims it is good for any range from 5 - 400m.