I have been wanting to try a SIII for a lower priced option. But too bad this one only has 50 moa. With a 20 moa base I guess you could get roughly 40 to 45 moa. that will get you close to 1500 with a good 338 and a 300 grain.
I am figuring with my .284 and whatever load I am gonna do I should be able to get to 1400 yards in around 45MOA it's gonna take some work with Burris rings to get the zero where it needs to be but it's worth a try I hope lol.