Interesting question, Levi.
Every Simonov I've seen had a chrome lined barrel, with the two standard exceptions: 1] original (not refurbished) barrels on early Tula's (they switched over to chrome lined barrel production in 1951? I think) and 2] all the Yugoslavians.
Chrome lining is easy to spot under good light --> a bright silvery inner ring (extremely thin) at the crown. Bluing does not take on the chrome.
Not my area, but I think Sino-Soviets were made with a mixture of Russian leftover parts and new Chinese parts. For example, there are some with Russian receivers and some with Chinese receivers.
But who made the barrels? Hmmm. Interesting question.
I really don't know because I've never owned one nor studied them. Someone else here will have to chime in on that, and whether any were seen without chrome lining. If so, that could indicate an early Russian barrel from Tula being re-used for the first Type 56's in China.
Do you have a Sino-Soviet SKS?
If so, would you share a close up picture of the barrel crown on it?
It might add to our knowledge.
