im new to the sks platform.  i picked up a norinco with matching numbers about 15 years ago for next to nothing as a pot sweetener in a larger trade.  back then, i put one mag through it and it slam fired.  i stored it away with intent to fix it up when i had time.  well, ive decided to work it up now.  im not really an sks guy but i can do minor work on a number of platforms.  i assumed it was the standard slam fire issue that was my problem.  after taking the bolt apart, i can say that the firing pin floats freely.  its not bound up or locked in the forward position.  im not exactly sure whats going on.  if i charge the weapon, and release the bolt with its full force (with an empty chamber) it will be not cocked, as if it just fired.  if i do this with a loaded chamber it will fire and continue to fire.  if i ride the bolt forward easily, it will stay cocked until the trigger is pulled.  its my understanding that the general slam fire issue is the pin being stuck in the forward position causing primer strikes. this pin is not stuck and moves freely, yet it still seems to slam fire.  anyone have any insight into this, or am i missing something in my understanding of slam firing?  thanks guys, for all the great info around here.  

cory.

There are a couple of reasons that an SKS firing pin will lock forward causing a slam fire and to even go full auto. The most common is cosmoline within the bolt and around the firing pin. I thought I had cleaned up my Yugo SKS pretty well, but when I took the firing pin out of the bolt, I found that was covered in cosmoline, so I scrubbed the heck out of it and have not had a slam fire.....yet.

The other reason for a slam fire to occur has to do with the tapered firing pin and a crater or volcano effect on the bolt face at the firing pin hole. Apparently at this juncture, the firing pin can become locked into the forward position causing a slam fire.

The best way to remedy the problem is to clean the firing pin channel thoroughly, check the bolt face for evidence of cratering and installing a spring loaded firing pin from Murray's Guns:

SKS firing pin

i think this may be a problem happening in the trigger group possibly the sear. ive just never been in this trigger group before.  looking at the sear, its a little chewed up but i cant tell to what degree.  the bolt and pin look and feel great.  i think i might try a new sear and check the angles on the hammer.

You might want to try buying or borrowing another trigger group for testing purposes and to see what is different on the current one you have.  There is a company making some new ones, but I can't remember off the top of my head who they are.  Saw them for $79 or so each, of course they looked like stamped trigger guards.

i did kinda try that lol.  i dont know anybody with one, but my local shop always had a couple on hand.   none back in stock yet since the hoopla.  im for sure going to locate one to test in there though before i spend the money on a new group, if the 15$ new sear dont solve it.

I doubt a new sear by itself will solve the problem, but I could be wrong.  Check the springs in the trigger group to be sure they are working correctly.

It sounds like it is in your trigger group to me. Keep Shooting.com sells the trigger groups.


I bet it is somthing with your sear or sear spring.

Agree look at trigger.

I had one mine do it and it was some debris in the sear area causing the problem.

You probably have what is referred to as "negative" engagement with the sear, which can be remedied with a file and hone, or a new sear.
Remove the trigger group from the rifle.
cock the hammer
slowly pull the trigger, watching the hammer movement.
The correct, "positive" engagement would be that the hammer actually moves backwards slightly before the sear releases it.
Neutral engagement is when the hammer just falls, and is okay.
Negative engagement is the hammer immediately starts to move forward, and is very dangerous, as you've experienced.
Here is a link about it:
http://www.sksboards.com/smf/index.php?topic=2830.0

I realize this an older post... I put the reply here for any future looks at this thread

Send the original off to kivaari and he can make it awesome again and correct the negative engagement.

Agreed!

http://www.kivaari.com/SKS%20Target%20Match.htm

I've been an SKS guy  for some time and I have to agree that the inertia of the bolt going forward is disengaging the trigger from sear. This would explain why it does not cock when you charge the weapon while empty. One other tip for anyone having trouble getting cosmoline out of tiny places or anywhere on or in the weapon. Do it outside but BRAKE CLEANER DISOLVES the cosmoline on contact practically. Yep but get yourself a new replacement trigger group if all other avenues fail.

Hey if this has not been fixed check out Murray's he makes new sears and hammers for the sks rifle as well as triggers firing pins and gas valves as well as other things you should give the sear and hammer a try it seems like that may be where the problem is.

>> as well as triggers firing pins<<

Right, my modified bolt is on its way back from Murray's as we speak. It's worth the $60.00 to me to help head off the "slam fire" matter.

There are two things that cause the slam fire issue.

Stuck firing pins and basically what amounts to a sharper shape on the bolt face.


Go to murray's gunsmithing website and buy you a spring loaded firing pin and send him your bolt and for like 30.00 he will do the "bolt face treatment" which will not only keep you from getting popped primers but also slam fires.

That could cause it to go full auto but not likely when the bolt is closed I wouldn't think.

You ever figure out the issue?