Yeah I know the PPC brass is expensive. We pay $AU170/100 for u/p cases.
The only other case that may make a good 30cal cast bullet cartridge is the 30 Herrit.

B.A.W.,
My calculations show that a 7.62x39mm case with a small primer pocket should be good for 77kpsi in the same chamber where a large primer pocket case is ok at 60 kpsi.

My experiments show that the large primer pocket case by Winchester is ok with 123 gr 21.1 gr W296, but not ok with 22.5 gr.

The PPC brass has a small primer pocket and all the commercial Boxer primed brass now offered for 7.62x39mm is now large primer pocket.

I did manage to get some old Remington 7.62x39mm brass with small primer pocket from Ebay [not available any more as new brass].

The PPC brass is VERY expensive.