Thursday, January 29, 2015

Firearm Forum Question: What's the Difference between .223 and 5.56 Ammo

Ask A Firearms Question:
What's the difference between .223 and 5.56 Ammo? I am new to the AR.
Thank you Stephanie Anderson.

The .223 Ammo Round shown next to the 5.56 Ammo round:
.223 versus 5.56 Mil Spec Cartridges ....

Blog Administrator -
The .223 round was the first evolution of the AR15 platform used in Vietnam. Later it was expanded to the 5.56 (5.56x45mm NATO) round. While the cartridge diameters are essential the same, the 5.56 is generally a little longer (see picture above), and the chamber pressure is greater than the .223 commercial round set by SAMMI for those chamber limits.
The bottom line is the rounds are almost identical except for the pressure tolerances and limits placed on the firearm. A 5.56 AR15 Platform Rifle can fire either a .223 or a 5.56 round, but a .223 chambered firearm cannot fire a 5.56 round. Always check the firearm to make sure it is stamped 5.56 Caliber (see pictures below). When the switchover occurred some of the older firearms still had .233 Caliber stamped on the rifle. When in doubt consult the firearm manual, or call the manufacturer with the serial number (S/N) and they will advised you.

The following photos show Modern AR15 Platform Assault Rifles clearly marked with 5.56 Caliber on frame:
Armalite ....
Bushmaster ....
Colt ....
DPMS ....
OlympicArms ....
STAG ....
NOTE: There are many makers and manufacturers of the AR15 in both the 5.56 and the 308 NATO Calibers, the above are just a sample ....

.223 Federal Ammunition (Ammo) ....

Remington .223 55gr Pointed Soft Point Hunting Ammo ....

5.56 Ammunition (Ammo) in bulk ....

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  1. Glad to see you are back posting, missed your daily topic posts.
    This is very informative, spot on, great for newbies.

  2. Firearms Guy here just wanting to let everyone know I had some urgent personal business that came up that's why I have not posted in awhile. I am back and should be posting a NEW Topic in a few days.

    Also, Mr. J. will now be my Site Administrator, he will respond to the posted comments and answer any emails.

  3. Great job here, but like I said rifles are not for me, I am a close in working sorta of quiet guy. The 22 is my preferred weapon.

  4. 2 years ago 5.56 ammo was pricy now it's cheaper than 223.

    1. That is so damn true. Like many I always bought the less expensive 223 for target shooting but now thee 5.56 in bulk is so much cheaper.

  5. .223 or 5.56 like a dog chasing its tail, give the AK47 any day.

  6. Armalite owner here. It all shoots and that's what really counts to me.

  7. I have switch almost entirely from 223 to the 5.56 as you stated because the 5.56 can be bought in bulk less per round cost.

  8. Quite aware of this I am but good information for the newbies getting started with the AR platform.

    1. Same here, and fully agree with your assessment.

  9. My brother has taught me well, a USMC Veteran.

  10. Aware of this fact. I have 2 AR15 platforms, but I prefer the AK47 7.62x39mm.

  11. Any combat veteran after 1980 should fully grasp this.

  12. i am thinking of suppressing my 300 black out and my 5.56 .
    i buy bulk ammo for these calibers because you have to do to much maintenance on bull nose cartridges .

    i do agree that 5.56 at the moment is much cheaper than 223 if bought in bulk .

  13. I have a STAG 5.56 but it just sits in my gun safe.
    I prefer my Yugo AK47.

  14. Otay says okay again and thanks.

  15. USMC Vet here, very familiar with this distinction.

  16. Not enough firepower for my taste.

  17. More valuable information, thank you.

  18. Very well explained, excellent job.

  19. I am finding it more expensive to purchase 223 ammo than 5.56, is anyone else having this problem?

    1. Just visit any Walmart and you can verify that


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