Two ways to go. If you want a SHTF/TEOTWAWKI rifle, the Trijicon ACOG with .308 reticle is the way to go.
For hunting/plinking, I would get one of the 1-4 0r 1.5-5 scopes from Leupold, Nikon, etc.
Of course, it you can afford it, a Swarovski, Nightforce, S&B.. .............
For those who have fought for it, freedom has a taste the protected will never know!
Or at least they did before political correctness