F/A MG34 stoppages...

[mggunner34]

So my MG34 has been chugging right along for a few years now with no real problems as long as I'm using decent ammo, I attended a desert shoot here in phoenix and ran into 4 total failures, out of 1100 yugo m76 sniper and 5000 or so Romanian 8mm. the failure rate isnt bad at all its just how it failed that bothers me...

both types of ammo are excellent and run well in the gun but I had 1 yugo and 1 Romanian fail to fire due to a light primer strike, upon inspection the strike on the primer is quite week not even penetrating half as much as the ammo that fired. Both rounds fired fine in my k98 after they failed in the MG. the FP spring looks good no debris in the channel for it either...

The other two failures are even more strange, while burning through a belt the gun just stopped firing, upon applying remedial action (charge the weapon) no round falls from the ejection port but if the trigger is pulled it continues to fire fine and runs through the rest of the belt with no issues seems like it just didn't advance the belt or it slipped through the feed pawls...

Can anyone shed any light on these issues? I know I may be nitpicking 4 failures out of 6100 rounds fired over the course of about 12 hours is actually pretty good, its just the nature of the failures makes me think there are parts that are ready to be replaced.

[60CPT]

If it were my gun, I would replace the recoil spring, the recuperator spring, and all the pawl springs in the feedblock. Old tired springs cause a lot of issues. New springs are cheap, and easy to replace. I would start there.

[mggunner34]

I did replace the main spring and the recuperator spring as well less thank 10,000 rounds ago so I think those are good, but feedblock springs is a great idea, does anyone know where to get new springs for the feedblock??

[JBaum]

Could it be simply that a couple cartridges had harder than normal primers? How about a grain or two of sand in the action? Did you check every shell to make sure a few weren't slightly over length or maybe slightly light on powder? An out of spec shell will stop the bolt from locking 100%, yet may be close enough to let the firing pin release lever raise to release the firing pin. A couple grains of sand on a shell that is fed into the chamber can do the same thing. Maybe a couple cartridges had a light load, with enough force to eject the shell but not enough to feed the next cartridge?

There are many possibilities as a cause to such a problem, but without establishing a pattern to the misfire, there is nothing to do to the gun that will result in perfection for every possible cause of a misfire that is perhaps not even caused by the gun.

General maintenance such as replacing every spring in the gun can be done, but save the old springs. You'll probably want to use them again if you find out replacing everything had no effect on the actual problem, whatever it may be. Did you oil the moving parts at any point in firing 6,100 rounds?

4 misfires out of 6,100 shots in a 75 year old gun shooting decades old ammo. I'm not sure I agree that there's a problem, or than anything you do will keep it from happening again.