Good question. I am no expert on this platform of firearms, so I can only speak to my limited experience and what I have read. Years ago I had one of the earliest examples of Chinese M14 to show up in this country. The fit and finish was atrocious and it looked plain terrible. The metal seemed too soft, the headspace was marginal at best, but, could it ever shoot. From what I read, the original Chinese guns were built by reverse engineering them to basically built a working copy. Later the machining and tooling was updated or perhaps changed is a better word to produce much better versions. Someone on here would be much better at explaining this than I .
In spite of all that, everyone of these guns that I have owned could shoot amazingly accurately.