Free: Contests & Raffles.
Nightforce if you can afford the $1,700 price tag. I have a buddy with your set up (.300RUM Sendero) that he topped with a Nightforce. He loves it. I have seen him whacking sillouettes at 1,200 yards, and he shot his bull at 800+ this year.If you can't swing the cost of the NF, I would go with the Leupold. I have a Rem 700 in 7mm Mag with a Leupy VXIII and target turrets. I love it, but I max out at 800 yards. My buddy (the guy with the NF) looked at my rig, nodded quietly and said "Yeah, this is a nice starter set up".