First time I took it out it jammed and locked up pretty good.  It was very clean, and probably pretty dry as far as oil.  Not wet.  I wiped a surface of Remoil on the bolt and carrier.  Could this have caused the issue?  It didn’t eject.  Ejector looks normal.  Wolf ammo shot fine in my other Saiga AK.  I was thinking maybe gas tube had leak or poor fit, but it looks tight.  Ideas of what to check?

Piston might be gummed up or tube is dirty.

did you completely disassemble the rifle prior to taking it out...and put everything back in?...perhaps the Spring on the piston?

Yes, totally disassembled and cleaned everything.  Soaked in CLP and mineral spirits, and then brushed off clean with brass brush.  No carbon on piston.  All springs in place.  Recoil spring with curly end in carrier.  Did I miss something?  Hole under gas block is open/free.  It is going to be a while before I can test fire again.  I just want to check everything beforehand.

As the previous poster says above me, check the short secondary piston inside the rear sight block. It might be gummed up after a while.

Not sure what I am looking for.  Looks clean, and moves freely.?

Does the weapon hand cycle....with the magazine open obviously.

In a safe direction(probably at a range) hand cycle through 10 rounds.....and to be sure the spring is on the piston in the rear sight block, correct?

Everything is there and in the correct orientation.  I am thinking either it was just too dry, or something is totally fucked on this rifle.  This was a recent Gunbroker purchase.  I will have an update over Labor Day.

My first sks, a norinco, was a single shot until i bought a replacement 'upper handguard` with a gas tube that better fit the piston.  Once the new gas tube was in place it ran like a top.  Almost like the previous owner shot a bunch of corrosive ammo and cleaned the whole gun except that gas tube as the piston itself was in excellent shape. Not sure if this helps

You saying the piston was slapping around loose inside ther gas tube?

Like said make sure secondary piston in rear sight base is clean too.

It sounds like it is short stroking and stuffing expanded empty case back in chamber.

Clean piston, make sure recoil spring is installed correctly and lubricate rifle than try it again. If still does it check gas port. Even rifles with badly pitted up gas pistons and tubes still run just fine from my experience.

I use grease on bolt cam surfaces and hammer face.

Update.  Went shooting with the SKS this weekend.  The first four or five shots jammed.  I had stove pipes, and empty rounds re-chambered and stuck.  Then it stopped.  Went through about five or six stripper clips without issue.  Then on the LAST shot, It fired, did not eject, and re-chambered the empty round, and locked up tight.  I had to whack the charging handle with a rubber gripped crescent wrench to pop it out.  What do I do next?   Attached File

Trash can?

I am think all new springs in the weapon and a new extractor.  There is no “ejector” in the design of the SKS, just a metal corner that the rounds smack into.  This ejector corner looks normal and is not worn, etc.

It sounds to me like the chamber is dirty and has a build up of lacquer or whatever. This would explain why it short strokes and would also explain the lock up after 20 to 30 rounds. I highly doubt the rifle is loading an empty back into the chamber. You might try cleaning that chamber well before spending more money on springs and such. If you have a short piece of cleaning rod with a good stiff brush and use a drill and hone/clean that chamber well with WD40 CLP or whatever works for you. Your cleaning rod can even be a old pistol brush as those work well plus give a bit of flex.  

That looks like a great SKS and is most certainly not a trash can gun. I've owned many a SKS and have had to clean the chamber on quite a few of them. After a few thousand rounds with the lacquer coated ammo you will notice build up which will create issues. Hope this helps and good luck.

Thanks for the hint.  I have CLP and will try that first.  The chamber “looks” clean, but could be totally caked with lacquer.  I did not consider this.  I will give it a soak and then a scrubbing.

On the “looks” of this gun, well I stripped the high gloss varnish off of it, and stained the stock M14 brownish/red, and then oiled it with tung oil.  I also think it looks good, although maybe not “correct”.

Might be something else but always go with the simple stuff first.

Clean the bejesus out of it (get real serious in the chamber!) and juice it up with lube before the next test fire.

Can't believe it is anything major as you got a couple of stripper clips to run through it.

When in doubt try different ammo also.