# 5.56 ammo in a 223??



## cj9271 (Aug 24, 2004)

any issues with shooting the 5.56 ammo in a 223.


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## snapperlicious (Aug 11, 2009)

You can shoot the 223 in the 5.56 but not the other way around.


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## MNsurf (Oct 21, 2011)

No. You CAN fire. 223 from a 5.56 however. 5.56 has a deeper throat. 223 Wylde will also fire both safely.

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## Brian10 (Sep 6, 2007)

If you're talking about an AR, most are actually 5.56 chambered. You can verify by checking the barrel which is usually stamped 223 or 5.56.


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## cj9271 (Aug 24, 2004)

yes, i am talking about the AR. one is a DPMS and one is a Sig


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## sotxks (Jul 10, 2011)

You can fire .223 from a 5.56, but cannot fire 5.56 from a .223. I own a 5.56 and buy nothing but .223 ammo for it. I have been told that the 5.56 round fires with a higher pressure than .223, therefore making it ok to use the .223 in it. If you use 5.56 in a .223 you could have some problems. This is what I have been told so I have just stuck to it. Anyone correct me if I'm wrong!


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## Bantam1 (Jun 26, 2007)

Just because the barrel is marked 5.56 may not mean the chamber is correct. I have seen out of spec chambers in several barrels.

Do not shoot 5.56 in a barrel rated for .223. 5.56 operates at much higher pressures than .223. It might work but you could have a kaboom one day.


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## CHARLIE (Jun 2, 2004)

Heard not to shoot 5.56 in 223's for years and have shot em (5.56 in 223's) for years.Never had an issue or have ever seen an issue. But dont do as I say find our yourself and do what you want to do.Fired hundred of rounds (5.56 ) through bolt guns and Mini 14's. Always figured a bolt gun was stronger than an auto anyway.


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## mas360 (Nov 21, 2006)

I've fired around 500 rounds of 5.56 in my CZ527, which is .223. So far I have not seen anything to be concerned with.


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## Brian10 (Sep 6, 2007)

Bantam1 said:


> Just because the barrel is marked 5.56 may not mean the chamber is correct. I have seen out of spec chambers in several barrels.


While this is possible in a custom build, this is highly unlikely in stock form from a major manufacturer.


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## Texas T (May 21, 2004)

http://cheaperthandirt.com/blog/?p=27893
More then you want to know


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## sixshootertexan (Nov 27, 2006)

It's strange that the reloading manuals I have have always claimed them to be the same. I can see why the military would want a case that is thicker to hold the higher pressures but did not know the neck lengths were different. Here's a chart I found on reamers for the two.

http://www.ar15barrels.com/data/223-556.pdf


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## Tomakazi (Dec 22, 2012)

When I received my AR15/M4/M-16 armorer's certification my instructor who was at one time an ex military advisor who worked for Colt stated that there was absolutely no difference between 5.56X45 and .223. Just as there is no difference between 7.62X51 and .308. 
Metric and decimal designation.


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## oc48 (Aug 13, 2005)

CHARLIE said:


> Heard not to shoot 5.56 in 223's for years and have shot em (5.56 in 223's) for years.Never had an issue or have ever seen an issue. But dont do as I say find our yourself and do what you want to do.Fired hundred of rounds (5.56 ) through bolt guns and Mini 14's. Always figured a bolt gun was stronger than an auto anyway.


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Bet


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## CDHknives (Mar 17, 2012)

Plain and simple, the pressure specs are different. 5.56NATO runs higher pressures.

Most rifles, even if labelled 223Rem, are built to the higher pressure spec of 5.56, so for all PRACTICAL purposes they are the same...with the exception that reloading manuals may be showing loads to 223Rem spec, not 5.56NATO spec. So, most people I have met consider them interchangeable...but the reloader needs to be careful.

Same issue exists for 9mm pistol ammo...NATO spec is really a high +p spec.


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## Texas T (May 21, 2004)

An excellent article on the differences or lack of between the 5.56 vs .223

http://thefiringline.com/forums/showthread.php?p=3952627


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## CDHknives (Mar 17, 2012)

Since the same assembly lines make mil and commercial brass for the 223/5.56 it has never surprised me that the brass differences are very similar to any other brand/lot variance.

NATO stamped ammo cycles my AR noticeably faster/harder than commercial 223 ammo, confirming that NATO spec ammo is higher pressure to me. Lots of pressure gun data out there that confirms it as well.

Again, for most people the difference is negligible.


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## dwilliams35 (Oct 8, 2006)

sotxks said:


> You can fire .223 from a 5.56, but cannot fire 5.56 from a .223. I own a 5.56 and buy nothing but .223 ammo for it. I have been told that the 5.56 round fires with a higher pressure than .223, therefore making it ok to use the .223 in it. If you use 5.56 in a .223 you could have some problems. This is what I have been told so I have just stuck to it. Anyone correct me if I'm wrong!


 The 5.56 CAN fire with higher pressures: you can have variations in loads just like anything else. The only difference is that the SAAMI spec for 5.56 is higher than their spec for the .223: if you've got a barrel that is proofed for the 5.56, you also cover the lower .223 spec. You can have downloaded 5.56 that are lower pressure than a pushing-the-limit .223.


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