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I have both 223 and 5.56 rounds on hand, pic related. My AR's lower says .223 caliber, but it has a 5.56 NATO barrel on it. I assume due to the barrel it's safe to shoot the 5.56, but what about the 223?

Before thinking about it much I've shot both through it, and nothing went wrong. Well, yet. After thinking about it I'd rather get some second opinions before chancing it again.

Internet literature and video research turned up inconclusive results, at least from what I found.

I have both 223 and 5.56 rounds on hand, pic related. My AR's lower says .223 caliber, but it has a 5.56 NATO barrel on it. I assume due to the barrel it's safe to shoot the 5.56, but what about the 223? Before thinking about it much I've shot both through it, and nothing went wrong. Well, yet. After thinking about it I'd rather get some second opinions before chancing it again. Internet literature and video research turned up inconclusive results, at least from what I found.

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[–] • 6 pts

You can shoot what the barrel says you can shoot. A 5.56 caliber barrel will shoot both rounds, but a 223 barrel will only shoot 223. This is because 5.56 has more pressure and can damage a 223 barrel, but not the other way around.

[–] • 4 pts

A .223 barrel can shoot 5.56... once. Disclaimer: Do not shoot 5.56 out of a .223 barrel.

[–] • 1 pt (edited )

https://www.youtube.com/watch?v=UU9O1OimCpE

https://bulkmunitions.com/5-56-vs-223-ammo-19-things-you-need-to-know/

https://exclusive.multibriefs.com/content/the-dangers-of-mixing-up-5.56x45mm-nato-and-.223-remington-rounds/recreation-leisure

Personally, I purchase the least expensive 5.56 ammo available that has good quality, reloadable, brass. I was buying Lake City M855 seconds in loose 2,000 round boxes and never had any problems of any kind with any of them. I burn that up in training and then reload the spent brass as a kind of "Mk318 mod 0 clone" using Hogdons CFE 223 and 62 grain Barnes TSX

https://www.hodgdonreloading.com/hodgdon/hodgdon-cfe-223

https://www.barnesbullets.com/product/tsx/?attribute_pa_bullet-diameter=0-224&attribute_pa_bullet-weight-gr=62&attribute_pa_bullet-type=tsx-bt&attribute_pa_rounds-per-box=50

On south Texas feral hogs it's not a "death ray", but it will do until the death ray gets here.

[–] • 0 pt (edited )

Correct answer goes to glock20!

As for which you should buy/when to use which, whatever .223 is cheapest for practice, 5.56 62gr M855 "green tip" in your SHTF mags because in a long enough barrel they are a match for the type of body armor you might have to worry about from the people most likely to attack you or your house with actual gear on.

[–] • 1 pt

Those M855 green tips aren't very expensive either. I've been getting 20 round boxes for about $14 at my local outdoors store and have been switching them into my mags. Gives me a chance to use the FMJs in there for a little practice, too.