.223 VS. 5.56 whats the difference?

[Micdub]

Did a search and came up with nothing. What is the difference between the two? I always thought they were the same .223 for civilian and 5.56 for military but someone told me that they are different. Whats the deal??

Thanks,
Mike

[blacklisted]

This will answer all of your questions:

http://www.ammo-oracle.com/body.htm

[EBWhite]

They are pretty much the same. .223 is older, 5.56 was a way to make everything metric....

[PanzerAce]

*cough*search button*cough*

and welcome to the forum

[blkA4alb]

They are pretty much the same

Don't go around saying that because its not true, and could get you hurt. Just read ammo-oracle as blacklisted posted and you'll understand. (Maybe not you specifically EBWhite but the thread starter) 5.56 produces higher chamber pressures than .223. Tight tolerance match .223 chambers won't necessarily take kindly to the increased pressure of the hot 5.56. but yes other than that they are dimensionally pretty much the same.

[Creampuff]

Tight tolerance match .223 chambers won't necessarily take kindly to the increased pressure of the hot 5.56. but yes other than that they are dimensionally pretty much the same.

For that reason, I usually only feed .223 into my Mini14. It was chambered for .223, so that is what it is fed. I mixed a box of 5.56 once into it by accident. No big deal, but it probably is something I should not continue to do. The newer Mini14's I hear are chambered for 5.56...but that would be sending this thread off track...sorry.

[Shoot-it]

I think once a month someone will ask this question and we will read it again next month someone should put it on a FAQ page.Must AR chambers are made for both but not all.

[rayra]

For that reason, I usually only feed .223 into my Mini14. It was chambered for .223, so that is what it is fed. I mixed a box of 5.56 once into it by accident. No big deal, but it probably is something I should not continue to do. The newer Mini14's I hear are chambered for 5.56...but that would be sending this thread off track...sorry.

That's not off-track at all, really. It very much is an issue of tolerances and milspec pressures.
You should only put milspec 5.56 ammo through a 5.56-tagged bbl. And .223 you can put through either.

Been a while since I read through that Ammo oracle data - anyone recall what it says about re-chambering a .223 bbl for 5.56? Is that all it would take?

I reload 5.56 brass for my Mini-14, but I only use a moderate powder loading, nowhere near the max SAAMI spec for .223. And there isn't enough difference in teh cartidges' interior dimensions to make a dangerous difference at the charges I'm loading. Never had any trouble whatsover, no chambering trouble, no extraction trouble, no apparent high-pressure indications at all.

Your experience may differ

[EBWhite]

As long as your using high .223 quality upper/barrel. You should be able to shoot any mil surplus 5.56 without issues. If your going for a nar nar overloaded hot round, then maybe it is best not to use it in that.