One thing to keep in mind.
The SKS’s (at least the Russian ones) have no spring on the firing pin, the firing pin kind of “free-floats” in the bolt.
So if it gets jammed or bent or fudged up in the forward position... you are in full auto until your clip is out.
The Soviets tried that, early on. Wasn't necessary. AK's, AR's M1A's don't have a firing pin spring, either. Soft primers are the only thing that have given me problems.