I see that they are all drilled cases. Any chance of getting some live stuff???
HC I've been thinkin' about what you were talking about having to find an outside source for the brass. So lets put our brains together. What other cartridges are based off of the 7.62x39 case head???
I know the .22 PPC and the 6mm PPC. However they are not as long as the 7.62x39. Maybe find a source of brass for the .22 PPC and the 6mm PPC and see if they offer unformed brass. If it is long enough then maybe it would easier then fire forming.