Junky, under the right conditions I'll shoot the 30mm out past 800yards. I will shoot at 400 if I see any shot developing but generally I use acm to get closer. Within 200.
I know you dedicated some time to the k4, but then the ki after that, and I don't know what plane you're on now. If you don't have a good idea where the tater round is going, I'd start close in again until you get the feel back. Once you feel you have that going for you, then don't hesitate to take some of the crazy shots. You're often rewarded for them, hopefully not with one of these weak taters though!