Hi,
My CZ 527 .223 makes very small crater marks on the primers of factory ammo.
It has done it since i got it new a month ago.
I have fired 39 rounds so far and each case has the same small mark and only very slight cratering on one side of the indentation made by the firing pin on the primer.
I have read, (since i dont reload), that it could be a slightly larger firing pin hole and the primer slightly flows back into the hole.
My question is, is this dangerous. Because if its not, then i wont worry about it, as the rifle is performing great.
Thanks.

Mik.
The 223 factory loads are quite hot. It is not unusual for primers to extrude into a loose firing pin hole in the bolt face. If it bothers you have the hole bushed. Not much to worry about.

quote:

Originally posted by Mik:
Hi,
My CZ 527 .223 makes very small crater marks on the primers of factory ammo.

My CZ 527 .222 does exactly the same thing. It also pierces pistol primers where my buddy's does not with the same load.

The size and the shape of the firing pin are not optimum and with size the diameter is too small with respect to the hole. Every load I have shot shows this effect to some degree. Many have been reduced loads. Cratering isn't always an indication of over pressure.

The firing pin holes probably can be bushed to reduce the diameter of the hole but I really fail to see what is going to be gained from a practical stand point.

Shoot and enjoy it roger

quote:

The firing pin holes probably can be bushed to reduce the diameter of the hole but I really fail to see what is going to be gained from a practical stand point.

I personally wouldn't do this unless there was rupturing of the primer and leakage of the gas.

In which case I'd return the gun to the manufacturer.

Thanks for the info so far.
I can have peace of mind now and know its not dangerous.
It does not peirce the primers, just a slight cratering on one side of the indentation.
Lovely rifle for the money.

quote:

Originally posted by Mik:Lovely rifle for the money.

YEP!

There is another possible contributor in your rifle and that is a slightly weak or short spring.Even that ,however, doesn't mean you don't have a perfectly usable fire arm. roger

If the cratering is just on one side as described, doesn't that suggest the bolt-face isn't square?
Cheers...
Con

Not too sure Con, does it matter, is it a bad thing?
Thanks.

quote:

Originally posted by Con:
If the cratering is just on one side as described, doesn't that suggest the bolt-face isn't square?Cheers...Con

No! It probably means that the firing pin is not concentric with the firing pin hole. roger

You didn't say if you are using commercial 223 Rem ammo or 5.56mm military surplus? The milsurp stuff has slightly different case dimensions and could cause this problem. Try changing to a different brand and see if the cratering persists.

Dave,
Im using factory sako ammo and factory remington Ammo, not military ammo.
I know not to use military ammo, as that is ment to be bad.
It does it with both brands.