I have a Norinco SKS. Beautiful rifle. I put a Murrays pin kit in it.
Refinished the stock, multiple coats of Tung oil.
It has never missed a beat while firing.
What's the advantage of the Murrarys kit?
Eliminates the risk of slam fire.
The free floating firing pin is replaced with a spring loaded pin.
If you have cosmoline or other crud in the firing pin channel the
free floating pin could stick forward. Accidental auto firing enabled.
Boy, do I regret not picking up an SKS at Fetlas a few years ago when they had a bunch of decent ones in a barrel for $79 each.