I keep wondering why no one tries the .308 Barnes kurtz. It is .308x1.5 inch and should fit the 7.62x39mm AK mags and action. The round can be hand loaded up to 52,000 psi (or more). A big advantage of this round is the use of the .308 Win case or mil surp cases or even spent mil surp 7.62x51mm blanks !!
A 7.62x39mm barrel could be rechambered to this round though the bore is a bit generous. Perhaps a paper patch or use of .311 inch bullets would help tighten up groups.
The .308x1.5 Barnes kurtz has been briefly mentioned here before but that was all.