I think it would be a great challenge to try to break 1K with some open sights. It would rank right up there with a 100 yard bow kill.
Probably you would need something like this http://www.phoenixprec.com/index.php
The highpower guys know a lot about this kind of stuff.
About 72 MOA of adjustment just like a long range scope
I wish my eyes were still good enough because I might give you a run for your money. Sounds like a lot of fun to me.