Dude, not being critical of the gunsmith (well yes I am) but if your "smith" installed this bullet guide and did not so much as check to see the bolt was closing and the bullets fed properly he's not much of a smith.
If you are going to do that, borrow his bolt carrier and piston assembly as well. Test the gas tube--if that don't work, use his bolt carrier/piston and your bolt to see how that works.
Does the gas piston have any wobble? If not that may be your problem. I've seen some that were screwed in so tight that they would not move. If this is the case, the piston could be 'dragging' or 'binding' against the gas tube wall and causing it not to cycle.
Easiest way to check is this...
I did a 91/30 with cold blue a few years back. Birchwood casey from wal-mart. It turned out awesome. I found out later why:
PREPARATION. You want every scrap of grease/oil off of the metal. All of it. If you've got oil/grease on your hands and you handle the metal before bluing it will look...
Acetone will remove paint without damaging the bluing. Once it's all stripped off, the metal will be dry so give it a good coat of oil or clp afterward.
In that case, I'd just purchase a spare and put it in the parts box. If at some point it does not cycle and you are in the field, you can still cycle it with the pump action. (lovely thing about the SPAS--best of both worlds) I'm sure on-line PDF how to manuals or you-tube videos of how to can...
If you opt to order the parts and do it yourself, be careful. That's awesomeness you've got there. I don't know anything about replacing the plunger; what is the "internet" thoughts behind replacing it? Does it wear easily? Is it just general principle? Is it a modification.
Unless it's worn or...
**do NOT weld, glue or otherwise mess with the piston: sjglenn hit the nail on the head...AK pistons are supposed to have proper 'wobble'.
This allows movement as the piston moves back, preventing it from binding or scrubbing against the gas tube wall. I have seen at least a half dozen Romanian...
http://www.brownells.com/.aspx/cid=0/k=ak+buffer/t=P/ksubmit=y/Products/All/search=ak_buffer
The recoil spring goes through it and it nests in the rear of the receiver.
You can take the extractor spring out and give a pull...see if you can extend it out a little bit. It may not be the "answer" for the long haul, but if you stretch it a little and it makes your occurrences less frequent at least you'll know you are on on the right path.
"new" extractor...
I don't know about needing to broken in...every one I've had fed and ejected right from jump street. I've built one with machine screws and my other build is a 'weld' build.
Never had a problem with either.
BUT
People tell me that welding may cause the receiver to bend or warp slightly. I...
Light grease/oil usually gives the hazy look you are talking about. Before attacking it with harsh stuff, I'd get a hot damp rag and some dawn dishwashing liquid and clean the stock good. Afterward, I'd wipe it down really well with regular ole' lemon pledge and see how she looks then.
I was planning on replacing the firing pin with a spring loaded one, but I have heard that its also good to replace the gas pistons...and the trigger is a little stiff. Any thoughts?
Other than 922r compliance, what is the 'good' reason to replace the gas piston? Just curious as I've shot...
That depends on what you mean by getting the "absolute most" out of it...from a practical perspective, a factory condition SKS = the most you can get.
Other than looks and (maybe) comfort/length of pull changing the stock will not make any difference in the performance of the rifle. Changing...