The NRA Whittington down in Raton has a nice 1,000 yard range. May be quite a drive for some of you guys in the Denver/Springs areas but should be worth the drive to find a range where even .50 BMG's are welcome.
As info the 1K range down there is closed right now for renovation. But the high-power silhouette range is still open and you can run any non-magnum that's not 22 centerfire there.