Not sure what happened there, but I wil try again.
I have two Norinco SKS's. One of them would not cycle after I purchased it and cleanned the packing grease out of it. What I found was that the main gas tube had "black crude" on the piston and in the tube. I took some very mild auto rubbing compound and a slow rotating portable battery operated drill. I took a shotgun cleanning jag, put a patch in it, put the jag on the shotgun cleanning rod, and chucked the rod in my drill. I then dipped it in the auto rubbing compound and worked the crude out of the the gas tube. Next, I chucked the piston in the drill chuck and then worked the rubbing compound over the the side of the piston to clean that up.
I then cleaned the heck out of everything to get all the grit out. Then oiled it and went to the range. It worked great.
The only problem I have had since then with my SKS's is that after using cheap "non corrosive" foreign ammo, if I don't clean the rifle right a way I have had a problem with the round not being able to fully insert in the chamber. The bolt won't completely close and it will be difficult for the bullet to be extacted.
To fix that, I took a spent cartridge case, and drilled out or enlarged the primer hole. I got the primer hole large enough to take a bolt that was the same thread size as a cleaning rod. Then out came the portable drill and the rubbing compound. I suspect that either corrosion or lacqure from the cases built up on the chamber walls. From then on I would clean an oil my SKS's religiously after coming home from the range and I haven't had a problem since.
I have two sons who like to shoot them and they have friends who like to go to the range as well. I buy 7.62x39 ammo by the 1000 round cases to keep the boys happy. If cleaned well right after firing, the SKS seems to work really well.
A couple of things I have done based on suggestions in this forum is to use a molly based grease on the trigger assembly to make it a bit smoother. I also added a recoil buffer to help reduce the metal to metal impact. Both SKS's I have are surpisingly accurate with cheap surplus ammo.
I have done some reloading for the 7.62x39 with winchester brass, and hunting bullets. Finding a handload that would cycle reliably and was within the right pressure range required more than one powder and a couple of trips to the range. The nice thing is that I found a load that will cycle well and is more accurate in my rifle. For something that cost so little they are surprisingly a lot of rifle for the money.
