So I decided to keep this rifle. Remington 700 .308 5r mil-spec. I added the Tac21 chassis and now need a scope. I want to do somethinG along the lines of the vortex viper 6.5-20. Would the viper with mil dot reticle and turrets work for out to 800-1000 yards? Or is the HS or pst more the way to go?