Yugo vs Norinco SKS?

[trueg50]

Yea, thats a known issue with the sks rifles. The firing pins are frequently cut flat on the tip, so from the side they form a plateau. This means the edges are slightly sharp, and can pop primers. What you want is a domed tip to the pin so it does not have sharper edges that can pop primers.

 

[Cee Zee]

I understood the problem with popped primers to be about primers that are too powerful or maybe too much powder in the shells. The extra power blows the primers out. I shot thousands of rounds of all kinds of ammo and never had a problem with my Norinco until I got a bad batch of Wolf ammo. I had 3 popped primers out of a box before I stopped shooting from that box. I repaired the slight damage that was done to my firing pin channel and put in the firing pin kit I had that came with a spring to push the firing pin back mainly because I got some slight damage to my original firing pin. I haven't had any more problems.

It's something to do with the ammo. My Norinco didn't suddenly develop this problem after thousands of rounds.

 

[bainter1212]

Some of the manufacturers have been known to use softer commercial spec primers instead of harder milspec primers. I suspect that is largely to blame for most of the popped primer issues you may run into.

 

[Hometeached1]

I'd go for the Yugo, since you already have a Norinco.

 

[Ignition Override]

trueg50:
At Murray's Gunsmithing, in Bowie TX (which worked on my chamber), Mr. Murray's best conclusion about the popped primer cause seems to focus on different amounts of freespace in chambers. Tula ammo is not the only type experiencing this. The contours of my Yugo firing pins are identical to other originals: nothing was modified.

To clarify, Mr. Murray suspects that during production in various countries, chambers were manufactured with different amounts of freespace.
This can be so tiny in some guns that excess pressure in the case is caused when the bullet has almost no room for forward movement, if I understood his replies to my questions correctly at SKSboards.

His conclusions about "freespace" (being the primary cause) result from the fact that After such precise chamber reaming, no more popped primers have been seen in the many rifles which were modified.
The dimensions of the popped primers' holes are the exact dimensions of the firing pins' holes, caused by the rearward gas flow due to such excess pressure in the case.

 

[Cee Zee]

Mr. Murray's best conclusion about the popped primer cause seems to focus on different amounts of freespace in chambers.

I wonder how that relates to the fact that my Norinco had maybe 10,000 rounds through it before it had a popped primer? I had heard that Murray believed it had something to do with extra pressure in some cartridges and that allowing more freespace in the chamber kept the pressure from building up so high in the cartridge that the primer popped out. I never really understood that explanation either though. But it does seem odd that it took that long for me to have a problem. I really hope it isn't an ammo issue because I have unopened 1,000 packages that haven't been tested. I'd hate to think a lot of them have problems and that's something I have been concerned about. But I didn't want to break the seal to test them.