Question for CanAm - 556 pressure

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calvados.boulard

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Hi CanAm,

I have a question for you if I may. In a thread dated November of 2012, you say there is no issue shooting Norinco 556 through a bolt chambered in 223. I'm under the impression that you were talking about the yellow boxed 556 headstamped Cj 93. I have some of the white box Norinco 556 headstamped Cj 95, that "seems" to fire quite a bit hotter than the previous yellow box. I base this only on my eyes, ears, and feel. I have not chronoed it. Is this whiteboxed CJ 95 safe to fire in a 223 chambered bolt?

Thanks CanAm,
Cal.
 
The 5.56 NATO round is slightly longer in the throat than a .223 Remington round. A .223 round has no problem in a 5.56 chamber because the throat of the chamber is longer and doesn't interfere with the case of the round. However, firing a 5.56 round in a tight, target .223 chamber (which would usually be the case in a target bolt) can cause an overpressure situation do to the chamber throat being too short and forcing the bullet head back OR damaging the brass as its chambered.#

CAN you shoot a 5.56 NATO round out of a 223 bolt gun? Yeah you can, once maybe twice, maybe even 100 times.... Should you, ABSOLUTELY NOT. It only takes one time firing the WRONG round out of the WRONG chamber to cause the WRONG results.

You can Google the SAAMI technical bulletins which state that SAAMI feels that shooting NATO pressure rounds in a 223 commerical chamber, is considered "dangerous" and shouldn't be done.

Eyes, Ears, and Feel is not exactly an accurate way to measure pressure. It only takes one round, and you may not have any of them.
 
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madcow said:
The 5.56 NATO round is slightly longer in the throat than a .223 Remington round. A .223 round has no problem in a 5.56 chamber because the throat of the chamber is longer and doesn't interfere with the case of the round. However, firing a 5.56 round in a tight, target .223 chamber (which would usually be the case in a target bolt) can cause an overpressure situation do to the chamber throat being too short and forcing the bullet head back OR damaging the brass as its chambered.#

CAN you shoot a 5.56 NATO round out of a 223 bolt gun? Yeah you can, once maybe twice, maybe even 100 times.... Should you, ABSOLUTELY NOT. It only takes one time firing the WRONG round out of the WRONG chamber to cause the WRONG results.

You can Google the SAAMI technical bulletins which state that SAAMI feels that shooting NATO pressure rounds in a 223 commerical chamber, is considered "dangerous" and shouldn't be done.
Click to expand...
Exactly.
This is why there is a .223 Wylde chambering.
 
Its best to check with the firearm manufacturer to see what the rifle is actually chambered for. CZ openly says their 527 rifles are chambered to shoot 5.56 surplus or .223 commercial.
 
I had several pierced primers shooting norinco yellow box in a bolt gun. I used to use it for plinking. I don't anymore.
 
If you have the ammo on hand, I would try it and watch for anything like pierced primers, hard bolt lift, or ejector marks on the case head. If nothing like this happens, carry on; if it does, discontinue use. Practically speaking, most factory .223 chambers will have a long enough throat to handle 5.56 and you will likely see some sort of warning sign well before catastrophic failure if you pay attention.

That being said, I would not have any sort of accuracy expectation out of Norinco 5.56 ammo, nor would I seek it out for a bolt gun. The case I bought was acceptable cheap blasting ammo for my AR with reloadable brass, but that's about it.
 
madcow said:
The 5.56 NATO round is slightly longer in the throat than a .223 Remington round. A .223 round has no problem in a 5.56 chamber because the throat of the chamber is longer and doesn't interfere with the case of the round. However, firing a 5.56 round in a tight, target .223 chamber (which would usually be the case in a target bolt) can cause an overpressure situation do to the chamber throat being too short and forcing the bullet head back OR damaging the brass as its chambered.#

CAN you shoot a 5.56 NATO round out of a 223 bolt gun? Yeah you can, once maybe twice, maybe even 100 times.... Should you, ABSOLUTELY NOT. It only takes one time firing the WRONG round out of the WRONG chamber to cause the WRONG results.

You can Google the SAAMI technical bulletins which state that SAAMI feels that shooting NATO pressure rounds in a 223 commercial chamber, is considered "dangerous" and shouldn't be done.

Eyes, Ears, and Feel is not exactly an accurate way to measure pressure. It only takes one round, and you may not have any of them.
Click to expand...

I'm waiting for 9mm Luger vs. 9x19 NATO nonsense next.... in reality there is some military ammo that may be too hot for commercial rifle (read can potentially exceed maximum pressure level for commercial ammo)... However, since NATO cartridge needs to be more or less uniformed between multiple countries (yet, each makes their own ammo with different specs) and multiple types of guns (that's why, just in case, they make larger throat in them), the chances of you getting this special purpose hot ammo is slim (just stay away from heavy long bullet surplus, e.g. 77gr bullets). At the end, 223 started as the same ammo as 5.56NATO.
 
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Trying to clear a few things up here. The issue of 5.56 in a .223 is not a pressure issue.They are measured differently and cannot be interchanged. The issue is not that 5.56 is to hot (or too high pressure) for a .223 bolt gun. The rifle can handle a lot of pressure. I would bet it can handle more than an AR can.

As mentioned above the issue is with the throat angle. This could cause high pressures.The key word there is could. Luckygunner had a great article about the differences between 5.56 and .223.I would encourage you to check that article out.

If it were my rifle I wouldn't hesitate to shoot 5.56. Having said that, when I had my Tikka I got terrible accuracy out of cheap 55gr ammo. It literally went all over the place. I think the fast twist rate (1-8) may have had something to do with it.
 
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