Norinco 223 - high pressure sign

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MiniMe

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Hi All

I took my XCR to the range this weekend and noticed that the brass was showing signs of high pressure, really high.
To the point that the primer is sticking out.
A buddy shot 5 rounds of my ammo with his 10.5" AR and the primer was very flattened as well and compared to his Norinco ammo that is from an older lot, even the recoil is noticeably more.

My XCR's barrel is stamped 223.
Ammo head stamp is C J 95

What could be the issue here? Ammo out of spec (too hot)?
Should I stop using this ammo in my XCR and stick to my AR for it??

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Thanks!
 
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Stop using it that looks quite dangerous. Can you post a photo of an unfired one with clear headstamp and another of the damaged headstamp. Also post a full case photo would like to see the case sides. Thank you for sharing
 
This is a great example of why using 5.56 in a .223 gun can be bad. This ammo is definitely too hot for this particular gun.
 
I attached more pics to to the first message.
This ammo came from a crate containing two spam cans.
These were the last few boxes of the first can.
I shot almost all other rounds in my S&W MP15T and even though the primers were a bit flattened they were not this bad at all.

I got this XCR late last year and didn't shoot it till now.
 
Hey guys just a heads up. Original xcrs had a known defect with the firing pin hole in the bolt face that was causing this. Also sometimes pierced primers.

XCRMonger (factory rep) even suggested that those who were too lazy to deal with warranties could take a dremmel just enough to break the edge of the firing pin hole on the boltface.

Try different factory ammo to confirm if it is the gun or ammo.
 
XCR's tend to be hard on primers! These rifles are made for 5.56 pressures but even .223 will show primers like this. Look at your boltface and see if it's been chamfered or not, I suspect yes. Rob Arm had a issue with some bolts that were punching holes in primers and they ended up chamfering them so they could still use them.

Mine is one of these and my primers look just like yours. I think the only thing that was suggested that you keep away from with these is Winchester white box .223. I would just stick with 5.56 Nato stuff and be good.
 
MiniMe said:
Note: The primers are not pierced through.
It is like the primer fire formed around the firing pin. But no hole.
Click to expand...

Its called primer cratering and it is a pressure sign. This doesn't necessarily mean that chamber pressures are too high for the rifle. it may mean that pressures are too high for those primers and that bolt face. In any event I wouldn't tempt fate by shooting more of that ammo in that gun although it may be fine in a different rifle.
 
A friends XCR had an issue with gas regulation in his. It made the cases start to extract before the pressure had dropped enough so it looked like the ammo was significantly over-pressure when it wasn't (at least not if the case was supported in the chamber). He had it fixed under warranty. I assume other brands of ammo don't look so bad? Could also try chronying some rounds and see what velocity it has; that'll tell you a lot more about pressure than any primer.

.223 and 5.56 actually have the same maximum pressure (55,000psi using the US method, 62,366psi using the NATO/European method). 5.56 is designed to produce that pressure in a looser chamber with a longer throat though. Sticking it in a tighter chamber with shorter throat (minimum spec .223) can cause the pressure to go above max. Nearly all commercial .223's have chambers and throats large enough to safely shoot 5.56 ammo but the lawyers make the companies print warnings not to anyway.
 
Look at the radius on the edge of that primer. Not flattened at all. The "cratering" around the firing pin indent is from the chamfering around the firing pin hole. For some strange reason, the bolts are made like that.
 
tiriaq said:
Look at the radius on the edge of that primer. Not flattened at all. The "cratering" around the firing pin indent is from the chamfering around the firing pin hole. For some strange reason, the bolts are made like that.
Click to expand...

If it was just the primer I wouldn't be too worried. But the primer appearance and the weird marks on the head of the case are concerning.
Granted it's hard to tell from the picture but it looks like the cases are really smacking into the bolt face.
 
dirtybarry said:
If it was just the primer I wouldn't be too worried. But the primer appearance and the weird marks on the head of the case are concerning.
Granted it's hard to tell from the picture but it looks like the cases are really smacking into the bolt face.
Click to expand...

There is a slot in the bolthead for the ejector. You can see the resulting ejector mark on the case beside the 95; directly opposite, the extractor has left its mark near the J.
The primer appearance is the result of the design of the rifle. The ejector and extractor marks are not the results of an over pressure cartridge.
 
tiriaq said:
Look at the radius on the edge of that primer. Not flattened at all. The "cratering" around the firing pin indent is from the chamfering around the firing pin hole. For some strange reason, the bolts are made like that.
Click to expand...

Good to hear from a gunsmith on this.
I was looking at the second photo, and also thinking that the primer radius doesnt look squashed.
The photo that MiniMe posted has a weird chamfer around the pin. Never seen that before. It looks chipped away.
 
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