First time at the range with 527, issue with Fiocchi 7.62X39 ammo, light striker

[Texas527]

Shot the 527 today and loved it. Kept them all in the black or better even shooting offhand. The 527 had no problem with ammo except the Fiocchi. The Fiocchi chambered but would not fire. The primers were dimpled, maybe a light striker issue? Seems to like the cheapest ammo the best. Might put a dot of red jig paint on the front sight. Will call CZ Monday and talk to a gunsmith about it. Love the set trigger, stock length and quality. I think we had one of of two guns with a brown stock and the only CZ. It was interesting to compare the results with the several AK's shooting the same ammo and the same distance. The same Fiocchi's that would not fire in the 527 had no issues in the AK. In the meantime, the Academy ammo shoots great.

[bobanddog]

Check the ammunition with a straightedge across the base of the cartridge, and see if there's a bit of a gap between the primer and the straightedge.  I had a similar issue with some .223 rounds, the primer was set so deep I could see and feel the difference.  If it passes that test, I would break out the calipers and compare the shoulder heights of the brass that didn't work with those that did before I worried about the rifle.  I suspect quality control on high demand ammunition like  7.62X39 and .223 has slipped of late.

Commercially sold bolt rifles can't afford to risk too deep a firing pin strike compared with military type autoloaders.  The firing pin in a bolt gun is right in front of the shooter's eye, and unless the bolt is shrouded, a pierced primer can vent hot gasses straight back and turn you into a Cyclops.  Most manufacturer's lean towards the conservative side when it comes to firing pin to primer striking depth to minimize that risk.

 

[Texas527]

Check the ammunition with a straightedge across the base of the cartridge, and see if there's a bit of a gap between the primer and the straightedge.  I had a similar issue with some .223 rounds, the primer was set so deep I could see and feel the difference.  If it passes that test, I would break out the calipers and compare the shoulder heights of the brass that didn't work with those that did before I worried about the rifle.  I suspect quality control on high demand ammunition like  7.62X39 and .223 has slipped of late.

Commercially sold bolt rifles can't afford to risk too deep a firing pin strike compared with military type autoloaders.  The firing pin in a bolt gun is right in front of the shooter's eye, and unless the bolt is shrouded, a pierced primer can vent hot gasses straight back and turn you into a Cyclops.  Most manufacturer's lean towards the conservative side when it comes to firing pin to primer striking depth to minimize that risk.

You are dead on. The primers are slightly recessed in the Fiocchi ammo. Thank you for the suggestions.

[bobanddog]

Happy to help, especially when it turns out to be the least expensive solution!

[truckjohn]

The issue typically isn't the ammo.. It's the little tab on the bottom of the striker has a burr on the end of it where it hits the overtravel stop on the receiver... so it doesn't go all the way forward like it's supposed to...

Primers are *SUPPOSED* to be slightly recessed into the back of the cartridge... It prevents firing out of battery should the primer be slightly proud of the cartridge....

Check out this post....

http://www.czfirearms.us/index.php?topic=50455.msg305657#msg305657

[bobanddog]

That could be, but the ammo I was referring to had noticeably deep-seated primers, far more extreme than any others I had tried.  (All of which fired just fine through the same rifle.)  I've used five different types of ammunition in that rifle and fired nearly 200 rounds through it at this point, and the only failures to fire occurred with the one box of Winchester ammunition.