I'm sure Pirate will be along soon to give you some sage advice but check his web site for information.
also check out
IMHO is you have built a few AK's you can build 1 yourself.
Most important is a good receiver plate and someone who can do the machining of the internals for semi-auto.
I have 1 converted to 8mm from .308. Ammo is getting expensive but what isn't
Here's mine home built on a Izzy kit, Halo 100% registered RSP & lot's of help from pirate. I restored the 1928 tri-pod
Here's a pair...... mine's on the left and Pirates in 30-06