I had a Romak that had the case separate at the base because the bolt was not fully rotated when fired, resulting in excessive head space. The hammer was not the stock shape and didn't hit the projection on the back of the bolt carrier that it is suppose to stop the hammer from hitting the firing pin if the bolt carrier is not fully forward. It had a 1.5mm receiver and nothing more happened than it blew the top cover off. It wasn't my gun and I was given Bulgarian yellow tip Maxim high pressure 7.62x54R ammo to shoot, which should never be shot in a AK variant.
P.S. My son is building a M-76 in .308 with a heavy target barrel. The barrel threads on a Winchester and Ruger are 1"-16tpi, which is just the right size to thread RPK trunnion which would give you a much stronger barrel to trunnion connection and you can put the gas block where you want and drill the gas port hole as small as needed to just cycle the action. I found that on a belt feed you need the gas pressure to push on the piston a lot longer before it's relieved to accuate the feed cam. Basically you need to convert a short stroke gas system to a long stroke gas system.