I've heard that the South African (PMP, I think) brass-cased 7.62x39mm is excellent ammo, particularly in terms of accuracy, compared to Russian ammo.
However, I'm a bit concerned about slam fire with the AK firing pin (no spring).
I suppose that is more of a soft/hard primer issue.
Also, how well does the brass case stand up to the notorious AK extractor?
Skorzeny