simply get a 308 take of barrel or other simular calibure and turn it down to fit the trunion inlarge the bolt face or turn down the rim on a few cases and go for it.
The main thing would be able to measure any changes in hed space super accuratly.
Id use a rommy trunion and bolt for a starters there cheap and also repersant the likely weakest of the AKs (possably) if they pass then Id be pretty confident a other variants perticualry the yugo trunuion would also be OK. I keep a really close eyeon my conversions and I dont load them up to near max. I still maintaine that the 300 savage is the way to go. The down side of course is there is no cheap surpluss or russian steel cased ammo but as a hand loader I dont care. I have pleanty of 7.62x39 guns for plinking and blasting.