Hi there,
Yes, I bought a bunch of Norinco red box non-corrosive. It is interesting because there seems to be a plethora of different feedback on it. The previous iteration, the non-corrosive white box - the Cabela's reviews on it seem to indicate that it may contain some corrosive rounds. That said, some members here who have used red box indicated that their experience is that it is not non-corrosive. I know that with corrosive all that is needed is to run hot water down the barrel, and I know lots of people who have decades of experience do this, but my limited monkey brain just can't get past my aversion to mixing water with metal. So I will take my chances with the Norinco red box non corrosive.
I can buy the non-surplus brass-cased 7.62x39 but I had a coronary when I saw the prices for a box of 20...at least compared to the Norinco.
Yes, the first thing I did was remove the bolt assembly and sure enough, the firing pin was stuck on protruding. And it was a bear removing that firing pin retaining pin (had to buy a vise and a new set of punches) but even once I got it out I couldn't get the free floating firing pin out without using pliers. Once I pulled it out - I saw the problem - it was completely grimed up with not just cosmoline but debris, bits of black stuff, gunk, etc. not just on the pin but throughout the channel. Certainly it was a slam fire waiting to happen. Cleaned the pin, channel as well as the retaining pin channel too (had to hammer it back in) - also took out the extractor and cleaned it too. On a second subsequent takedown, I took everything back out and boiled it all individually...then put it back together. That rattling noise of the bolt assembly now is music to my ears.
Only other thing is how stuck/stiff that handguard release lever is - I needed a screwdriver/punch to move it from the first to second detent and even then I had to get a butter knife to pry the handguard off. I wonder whether the handguard was a refurb as the switch does not freely move by hand. Once I got it off I cleaned the gas tube, piston rod as well as that other piston / rod thing under spring pressure (thankfully the lever to move it to release that was easier by then, because that darn handguard was already off.
I also tested the trigger and had my daughter film the hammer being released to see what kind of sear engagement I got. While my slow mo review of the video shows it is not negative, it wasn't positive either, but apparently neutral is very common with the Russian SKSes. I think I will just leave it as is.