I built an AR-15 in 6.8 SPC last year as a dedicated hunting rifle for whitetail deer.
The Trijicon AccuPoint 3 - 9 X 40 makes an excellent hunting scope, and comes with several reticles from which to choose, illuminated by either ambient light through fiber optics, or tritium in low-light conditions. The glass is crystal clear and the scope weighs in at about 13 oz. and has a 1" scope body. I chose the green mil-dot reticle, and have been very happy with it. It can be had for around $600 with careful shopping on the internet.
I mounted mine on a LaRue LT-104 SPR mount.
XD-40 service, XD-9sc, member GeorgiaCarry.Org, National Rifle Association, Gun Owners of America, North American Hunting Club, Rocky Mountain Elk Foundation