DPMS has 7.62x39 rifles and parts listed on their website.
Personally I want to go the 80% route. (no paperwork!)
DPMS is on the low end of acceptable for ARs.
And you can also do “no paperwork” with a private buy of a lower.
An 80% receiver requires about $300 in tooling and jigs to complete. Which means it costs more than finding a lower from a private seller.