Blown Primers Wold 5.45x39

[Flyboy73]

I was shooting my AK-74 semi auto and had a ammo problem. I had a failure to feed and I pulled the mag to check the problem. I noticed that the top cartridge was loose and not at the top of the feed lips. I then found something binding the follower and found it was a crushed primer.

I then pulled the gun apart and found another primer. I checked the gun over and it looked good.

I found the two cases and there was no primers in the pocket. I put it back together and put another 10 rounds though it with no problems.

I have over 200 rounds through this gun and never had a problem.

I was thinking it might have been the ammo. Something not set right with the primers?

You can see the two primers and some others cases i fired after in the Pic.

Any other thoughts on why this happened?

Brion

 

[Hizzie]

Appears to have signs of high pressure. Look at the raised ring around the firing pin indentation.

 

[Flyboy73]

Appears to have signs of high pressure. Look at the raised ring around the firing pin indentation

Any idea on what might have caused it?


Brion

 

[gunnutery]

Appears to have signs of high pressure. Look at the raised ring around the firing pin indentation

I've never heard that before, what causes raised ring during high pressure?

I guess it's hard to tell in the pic, but it doesn't appear that the other primers are backed out any. Could the gas port been plugged up for a couple rounds?

 

[animator]

Of the thousands of rounds of wolf 5.45x39 I've fired, I've had that happen exactly one time. I've also had one case with a primer loaded in backwards. And maybe 5 or less multiple-strike-no-fire primered cases.


So I'd say it's a very rare occurrence, and even more rare to see it twice in one sitting.


The raised ring is caused by the primer being forced against the bolt face, and basically molding itself around the firing pin and firing pin hole. It can be a sign of excessive pressure, meaning the cartridge may have been overloaded when fired.


I've had it happen with wolf .223 as well, exactly one time. Found the primer bouncing around the FCG when I was cleaning the rifle after shooting. Otherwise I would have never known it happened...

 

[Flyboy73]

I wouldn't have noticed it, if the primer had not jammed itself in the magazine.

Brion

 

[ants]

Well...

... you and I buy cheap ammo and we get occasional anomalies.
What should expect that. It ain't the gun, it's the ammo.

 

[stubbicatt]

Here's the deal. I do not know what caused the primers to back out of the pockets. I can tell you that the annular ring in the primers which are still in the cartridges is likely caused rather than by *excessive* pressure by the fact that the bolt face is radiused in the firing pin aperture on most of these Kalashnikovs. So even with standard rifle pressures, you will get this ring in most Kalashnikovs.

Could be that the primer diameter was out of spec, or the primer pocket was swaged a bit too large, and the crimp was inadequate to keep these in.

Lastly and while it is difficult to be sure, all of the primers in the remaining cases appear to have backed out a little bit which suggests to me an excessive headspace condition which should be diagnosed before any more firing.

Internet advice is worth what you paid for it I guess.

Good luck.