Hey gang--
I own a 1978-production O-series Yugoslavian SKS, which I use both for hunting and as my MBR.
It is a rearsenaled example with a few non-matching #'s but otherwise it is entirely original. The bolt was taken apart and the FP channel cleaned completely, and I did a light polish job to the FP itself with Flitz and a Dremel. I can report that there is no spring on the FP, as it is OEM also.
I have heard many comments about potential problems arising from the use of American ammo loaded with soft, non-MilSpec primers in these rifles, so I endeavored to test my rifle for the possibility of slam-firing.
This became a personal issue after a thwarted home invasion -wherein the sound of my SKS's action chambering a round seems to have been plenty of incentive to run the little punks off- ensued recently.
The chambered round, upon extraction, had a very deep dent in the center of the primer, and I was quite concerned about how close I may have come to giving the would-be thieves an inadvertant warning shot while also ventilating my roof!
So, this is what I did...
I loaded up several x39 rounds with all of the various primers I had laying around that would fit and proceeded to chamber and rechamber them (at the range, all safety protocols adhered to) until either they burst from the repeated FP impact or until I got tired of the exercise.
I got tired first, I am happy to report.
I had standard CCI 200 rifle primers, CCI 250 magnum primers, Winchester LRM and Remington LR primers available for this test.
None of the primers detonated after 20 full-retraction releases of the bolt carrier. They all dented deeply on the first strike but subsequent slammings did nothing apparent to deepen the strike craters.
I also had several rounds of factory UMC FMJ ammo with their small, gold-colored primers--these were affected even less than the LR primers were, as their dents were more shallow.
Just for S&G I loaded and extracted one of my handloads over 50 times (loaded with H4895 and a CCI 250 primer), and it refused to fire until I squeezed the trigger. I did the same with a round loaded with a CCI 200 primer--same thing, though I gave up and rang the 400M gong with it after my finger got sore from crankin' the bolt back several dozen times.
It would appear that most slamfires are the result of poor maintenance, as the most likely cause would be that which prevents the FP from bouncing off the primer lightly enough--something like a bit of debris in the FP channel, dried Cosmo, or a bent FP. And a bent SKS FP seems like it would be rare, as well as easily remedied.
Maybe my rifle is an exception, but I doubt it.
If in doubt about the primers in your loadings, take your new ammo and your SKS to the range and do as I did with one or two of them--if it's gonna slamfire it ought to do it within 5 or 10 loadings, I would think. Fifty repititions seemed like overkill, and that is exactly why I did it.
But now I know I don't have anything to worry about on that front, and that made it worthwhile to me.
Best regards,
Fast