.223 vs. 5.56 Nato - What You Thought Might Not Be True!

[skydiver]

Great articles. Thought I'd pass along.

Blue Skies!

5.56 vs .223 – What You Know May Be Wrong - LuckyGunner.com Labs

<broken link removed>

Read More

 

[Bon Sauvage]

I'm glad you did my friend. Thank you!

 

[skydiver]

I'm glad you did my friend. Thank you!

You're welcome!

 

[deadshot2]

Nicely done article. Didn't reveal any earth shattering info though.

Over the years some have taken the SAAMI "Warning' that a 5.56mm Nato cartridge fired in a .223 Chamber COULD to a level of "It will blow up your gun, make you sterile, and cause your children to be drug addicts, etc.".

Buried deep in the article was a brief explanation that some "Foreign" manufacturers load their rounds a little "stiff" and the 5.56 mm chamber just allows for the rifle to handle the pressure better.

Again, a good article and one should keep it handy for when they need something similar to this---

 

[accessbob]

Good article and very informative for those of us who have little experience with either. Thanks for posting.

 

[Darkker]

FINALLY!!!
I agree with deadshot exactly.
Another interesting thing about the SAAMI "warning", is that they don't warn against using CIP spec ammo in a SAAMI chamber; only about NATO spec.

This should be sticky!

 

[Spitpatch]

My father would stare at me blankly when I'd come up with ("crap") such as "you shouldn't shoot 5.56 in your .223". Then he would keep doing what he was doing because it worked just fine.

I miss him.

 

[AMProducts]

FINALLY!!!
I agree with deadshot exactly.
Another interesting thing about the SAAMI "warning", is that they don't warn against using CIP spec ammo in a SAAMI chamber; only about NATO spec.

This should be sticky!

CIP spec is roughly the same as SAAMI spec, the major difference is the units of measurement are all SI instead of IPS. The other difference between CIP and SAAMI is CIP proofs guns with 2 shots at 25% overcharge, and SAAMI spec proofs at 40% overcharge for 1 shot. Also, SAAMI is just a standards organization, CIP actually handles proofing of guns, barrels, and ammunition before they can be sold.

 

[Darkker]

CIP spec is roughly the same as SAAMI spec, the major difference is the units of measurement are all SI instead of IPS. The other difference between CIP and SAAMI is CIP proofs guns with 2 shots at 25% overcharge, and SAAMI spec proofs at 40% overcharge for 1 shot. Also, SAAMI is just a standards organization, CIP actually handles proofing of guns, barrels, and ammunition before they can be sold.

That was my whole point....
SAAMI went out of their way to warn against using NATO spec ammo(because of pressures) in a SAAMI chamber, BUT NOT CIP spec.....Which mirrors the NATO spec....

So yes, they are ROUGHLY the same. Just as NATO and SAAMI are roughly the same.

CIP standard is 62,000 PSI, SAAMI is 55,000 PSI.
CIP Proofs using that 25% on centerfire rifles. Auto-pistol, revolvers, and rimfire are 30% over.
They use BAR, which is not an SI unit, but is from the NIST.

 

[Miravox]

Were it not for the SOP concerning DUII in the FAA, we'd all be SOL!

 

[pdx lefty]

Great article. Thought I'd pass along.

Blue Skies!

5.56 vs .223 – What You Know May Be Wrong - LuckyGunner.com Labs

Thanks for the info!

Lefty.

 

[Nutty4Guns]

Were it not for the SOP concerning DUII in the FAA, we'd all be SOL!

In a manner of speaking, yes.

 

[deadshot2]

CIP spec is roughly the same as SAAMI spec, the major difference is the units of measurement are all SI instead of IPS. The other difference between CIP and SAAMI is CIP proofs guns with 2 shots at 25% overcharge, and SAAMI spec proofs at 40% overcharge for 1 shot. Also, SAAMI is just a standards organization, CIP actually handles proofing of guns, barrels, and ammunition before they can be sold.

Too damn complicated. I prefer the OLD WAY. You know, brew up a load, tie the "gun" to a tree, use a long string to pull the trigger, and Presto! Test finished. If he rifle is still tied to the tree and in one piece it was a successful test. If the bolt was a little hard to open, back down a half teaspoon or so

BTW, I hate abbreviations. Used to be married to a gal that couldn't speak in complete words. An accountant and everyting was in 3-4 letter acronyms. I turned her into a two letter acronym --- EX

 

[AMProducts]

When it comes to all this stuff... I am all scientific and stuff

Anyways, I thought I would look all this stuff up, which reminded me I needed to copy my CIP drawings off my thumbdrive. So after that, I did some checking, the Pmax for ".223 Remington" under CIP is 4300 BAR (bar is SI, 1bar = 10kPa) which is over 62,000 PSI. I also checked the throat dimensions for .223 rem in both CIP and SAAMI, and hmm guess what? They're the same! (other than being metric) I'll admit, I've heard all of the back and forth on the "unsafe combination" for years, and I've heard a wide variance of opinion as to exactly why. I'll check the nato chamber drawings next time I stop by my old work (where we have those kinds of things).

 

[deen_ad]

I see ads for .223/5.56 ammo all the time. I ask them which is it as there's adifference. Usually they just it's both. but in truyth it's not and I wnat to absolutley know which I'm buying.

One of the gun mags had a story on this also a few years ago, they showed a 5.56 at minimum spec OAL next to a .223 at maximum OAL, there was quite a difference in the leade.

 

[AMProducts]

Supposedly there are two differences between 5.56 which are interrelated... the 5.56mm chamber is supposed to have a longer and more gradual throat, which means the 5.56 can be loaded hotter as engraving force is reduced. However a hotter round fired in a gun with a tight throat will result in dramatically higher chamber pressures. Just ask any benchrest shooters who tried to load a bullet .010" short of the throat with a max load (blown primers anyone?). It seems CIP possibly got around this problem by accepting a higher Pmax and then using the same chamber dimensions as .223 rem.

 

[Darkker]

The NATO chamber(Yes I am aware, as the article points out, that there are a ba-zillion different reamers with the same name) has a longer throat, or leade. That is for simplicity sake. If you build in a longer throat, then you can shoot longer bullets, like Tracers, sabots, SLAP, etc WITHOUT having to re-chamber EVERY gun. IS SOME military ammo hotter? Perhaps, but that depends upon how one measures the pressure, and WHERE.

The whole point to that article was That there is little PRACTICAL difference. Provided you aren't shooting some Odd loading, just standard BALL ammo(M855, SS109) That they are safe for the BULK of the SAAMI chambers out there. If you read through the article, he even shows pressure data. The arguement that Military ammo is "Hotter" is at best symantics, comparing ball ammo to SAAMI ammo.
There is NO difference in brass spec, and when tested equally(as shown in the article) there is no appreciable pressure difference. CAN something be wrong and you have a bullet stick the lands? Of course! CAN there be a bad lot of "SURPLUS" ammo? Of course!
ALL Rugers, Savage, Etc build and heat treat their rifles to withstand the highest pressure chambered. When a factory builds a reciever, that "blank" isn't spec'd as a 223, or 270. It is a long action, or short depending upon the production run. So they are heat treated the same.

 

[skydiver]

Found another great article on the subject:

<broken link removed>

 

[Darkker]

That article isn't that exhaustive, or as complete as Dear old Sweeney-son would like us to believe.

If you want COMPLETE, timelined history of WHAT, HOW, WHEN, WHERE, WHY.
Read this(and get some eye drops ready, it isn't short):
The Gun Zone -- A 5.56 X 45mm "Timeline" Prologue

 

[BAMCIS]

Were it not for the SOP concerning DUII in the FAA, we'd all be SOL!

LOL