I just got my first SKS one week ago today. It was an impulse buy, something I did not know I would be doing that day. The seller advertised it as an /26\ rifle that he had only shot a little and that still had some cosmoline to clean out. He also claimed it was from the 1950's. Here is the gun.
The seller was wrong, it was an /136\ gun.
As I researched further it appeared that my gun dates from 1973, so the seller was wrong again. I learned about the dating of non-/26\ guns in the section of the Chinese SKS Guide called Dating the Chinese SKS. By a large coincidence, figure 2 there showed a 1.8 million serial numbered gun that looked like it might be a /136\ from the same year as mine, since mine is also a 1.8 million serial number. The arsenal stamp is hard to read so I may be wrong on that. The caption to the picture said that that gun had the late features to include a pinned barrel. I thought that was interesting because my serial number is only a couple of thousand numbers earlier than the one in the photo, but my barrel is threaded. The guide picture is below, followed by my gun.
Anyway, for what it is worth, it might narrow the time frame for the switch from threaded to pinned or it might not. I am quite new to the SKS so I could easily be missing something here.
I got out to shoot my new gun today, and I may have found why the seller got rid of it. Ejection was weak, with a couple of empties barely getting out of the gun and one stovepipe. Upon disassembly I found that some of the extractor spring was in tiny pieces and the remainder barely stuck out of its hole. I have a new one on the way. I hope that fixes it.
That is my story on my entry to the SKS community. I doubt that I will stop with only one SKS. Those Russian ones look pretty cool.