5.56mm NATO versus 223 Remington Chamber Differences

[Iraqgunz]

If you had a Colt, DD, BCM, or even an LMT I would probably go out on a limb and say that your chamber is probably not in doubt. That's because they are known to be consistent.

With Bushmaster it's anyone's guess as they have proven to be inconsistent. You would need to do a chamber casting or you could use Ned Christiansens chamber checker.

Ultimately if you really want to know get some M855 or M193 and test some rounds. Look for blown primers or rounds that fail to extract.

My two Bushmasters have .223/5.56 on the receiver, but they are marked 5.56 NATO on the barrel. I called Bushmaster & they said the rifles could fire both .223/5.56. Is this BS? Should I just stick with .223 ammo? Thanks.

[weggy]

Great post- sticky quality.

[richc2048]

So this was mentioned in page 2 of this thread and it cannot tell if it was answered. I purchased some mixed .223 and 5.56 brass. Most are lake city, some are federal 5.56, some are .223 and some I can't tell the markings.

As long as I load to .223 load data I'm good to go?
Also, no one seems to want to publish 5.56 loads. Where can I find some for H-335 and hodgens CCE 223?

I separated the lake city from everything else. I have some ss-109 projectiles I would like to load to original 5.56 loads. Thank you in advance for all your help guys.

[TomD]

The latest Hornady manual has 5.56 data.

[hunt_ak]

We've established the difference between .223 Remington and 5.56 NATO...

How about .223 Wylde vs. 5.56 NATO?

[patrick sweeney]

5.56 leade, with a tighter neck/throat than 5.56, but not as tight as a minimum-dimension .223 neck.

Basically, to gain the best accuracy that a .223 could deliver, while controlling pressure like a 5.56.

[markm]

5.56 leade, with a tighter neck/throat than 5.56, but not as tight as a minimum-dimension .223 neck.

Basically, to gain the best accuracy that a .223 could deliver, while controlling pressure like a 5.56.

That's my understanding of it too.... The wylde chambers, however, were known for popping primers and stuff with the hot Q3131 WIN M193 variant. I'd seen signs, and I had an instructor mention the issues at a Patrol Rifle class also.

I can remember my Wylde chamber giving me weird buldges in some of my brass on full house loads too. Kinda spooked me.

[Steel head]

The Wylde neck is actually looser than 5.56

[patrick sweeney]

Hmmm, time to go back and pore over the drawings.

[constructor]

That's my understanding of it too.... The wylde chambers, however, were known for popping primers and stuff with the hot Q3131 WIN M193 variant. I'd seen signs, and I had an instructor mention the issues at a Patrol Rifle class also.

I can remember my Wylde chamber giving me weird buldges in some of my brass on full house loads too. Kinda spooked me.

Sounds like you had other problems. When the headspace is correct the Wylde chambers will shoot any load a 5.56 will.

Look at the difference in the 5.56Nato and 223 Wylde chamber drawings. The 223 Wylde is actually larger in most dimensions and has a longer freebore. The difference is the freebore of the Wylde is .2245 in diameter to properly align the bullet the 5.56 Nato freebore is .226" or .002" larger diameter than the bullet.
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