.223 vs 5.56 NATO

[Ron37388]

I just bought a new MP15 Sport. The barrel is stamped 5.56 NATO. After reading some online articles about NEVER using 5.56 ammo in a rifle chambered .223, I am a bit confused. I thought I was getting a .223. From what I have read I should be able to use either ammo in a weapon stamped 5.56 NATO. Anyone have some info on this. Plus, why would S&W market a weapon as a .223 and then stamp the barrel 5.56 NATO? I bought WPA Military Grade .223, FMJ, 55 gn, made in Russia. Is this ammo safe to use in my rifle?
Thanks for any info you may give.

[azmick]

you can shoot 223 in a 5.56 chamber.
YOU can shoot 5.56 in a 223 chamber, I will not.
I bought a 5.56 chambered barrel exactly for that reason.
I don't care for steel cased Russian ammo, it is the only stuff that I ever had trouble with (one of my sons bought it, not me).

[Injunbro]

Some .223 rifles, like Brownings, that have tighter chambers have issues chambering 5.56 NATO rounds because the NATO round is slightly longer; these rifles are very accurate because of their tight specs. There should be no problem chambering or shooting either round in a barrel marked 5.56. The Russian ammo is probably safe in your gun but I imagine you'll have issues w/ it jamming... the difference in price for better ammo is small, I buy Federal for use in my M&P15 Sport.

[carl418]

Not much to add to this except to say that what Injunbro and Mick have said is spot on. You can shoot 223 or 5.56 in a 5.56 barrel but NOT the other way around. Any time you buy an AR 15, make sure it's a 5.56 so you can shoot either round in it.

As far as the ammo, I also buy Federal. Never had a problem with it, even when I bought it in bulk.

[DocZeus]

I've never shot any steel-cased/Russian ammo in any of my AR's, but years ago, a buddy of mine did in his Colt Delta-Match HBAR, and after a few hundred rounds of rapid-firing, he started to have serious extraction/jamming problems.....this continued for the rest of the session, and when he got it home and broke it down, the varnish they coated those steel casings with had melted from the heat of rapid firing, and stained the chamber with varnish.....it REALLY gummed-up the action, and he REALLY had to scrub hard to get it all out, took a few cleanings, IIRC.

I dunno if they're still coating them with that gunk, but it'll never come near MY AR's chambers, if I can help it. Get the GOOD stuff (brass), and your AR will LOVE you for it.

Federal American Eagle® - .223 Rem. 55gr FMJ 1000/Box - Natchez Shooters Supplies American Eagle® - .223 Rem. 55gr FMJ 1000/Box

Federal Lake City 223/5.56 Nato 62gr Green Tip 900/BOX - Natchez Shooters Supplies Lake City 223/5.56 Nato 62gr Green Tip 900/BOX

Federal Lake City 5.56 62gr XM855/SS109 Green Tip 1000/Box - Natchez Shooters Supplies Lake City 5.56 62gr XM855/SS109 Green Tip 1000/Box

DocZeus
AKA
David

[azmick]

This is what I have been buying, made by Federal, $5.97/box of 20 at wallyworld

Walmart.com: American Eagle 223 REM 55GR FMJ 20rd: Hunting

[Ron37388]

Thanks for all the good info. I feel better about the gun being stamped 5.56 NATO. At least I know I can use either ammo. I read a lot of reviews on the WPA ammo I bought and they all were very good. Even a couple with the S&W MP15 said they had no problems. I'll try it and see what happens. DocZeus, they don't coat the casings with varnish anymore. I'll post my results from the range.

[ElectroMotive]

I just put 1,000rds of 62gr WPA, on full auto, through an AR with no additional lube. I mixed in brass cased M855, Horady TAP, and Black Hills reman. No jams, no failures.

Keep your AR wet with good lube, use good mags, and it should eat what you feed it.


Fir the record, WPA is Wolf Performance Ammo. It is now loaded by Barnual, as Wolf and Tula parted ways.

[sigmaman1522]

The 5.56 Nato is just a big brother to the 223. The round is the same except the 5.56 Nato just has more powder in the round . You should be able to shoot both but i personally would shoot both in the gun stamped for 5.56 NATO , i would not shoot 5.56 nato in the 223 stamped gun just for safety measures.

[ElectroMotive]

There are some differences in size between 5.56x45 and .223Rem. The shoulder angle is the most obvious. Hence in some bolt guns, a 5.56 wont chamber.