A nice 3-9x40 scope should do you well, that is what have on my barrel at the moment.
I did have a 6-18x50 on it for a short time which made load development checking really easy at 100yds.
Did you get the Spec II chamber in your AR? mine is still the original chamber.
Have you been to this site? http://68forums.com/forums/forum.ph...e1881317fa