Dumbass question: 5.56MM and .223 chamberings. Am I getting this right?

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September 05, 2022, 05:32 PM
Dumbass question: 5.56MM and .223 chamberings. Am I getting this right?
Originally posted by sigfreund:
Originally posted by MikeinNC:
Just to add some confusion to the mix. The “NATO” 5.56 round is/was the M193 55grain FMJ lead core bullet.

Ah, something I didn’t think about earlier.
Does that mean until the M855 cartridge came along that it was unsafe to shoot M193 ammunition in 223 Remington chambers because it was the prohibited NATO round, but as soon as it was declared to not be the NATO cartridge, it suddenly, ipso facto, became safe? If something like the M855A1 becomes the official NATO cartridge, will that mean all the hoarded ordinary M855 will be good to shoot in 223 chambers? Confused

That seems to be what some would have us believe. Or maybe not. Roll Eyes

I can’t answer your question as I only have ARs with 5.56 NATO stamped on the barrels. And I shoot anything thru them.

In The bolt gun I have in 223, I had load for that gun.

But…when the M193 round was “The” round, people were advised not to shoot it in 223 chambers. The difference is twofold. One, the military measures pressure chamber different than SAAMI does. secondly,the military chamber has a longer leade that is different from the regular 223 chamber leade. That affect pressure also.

But no, the old M193 nato round, once being regulated to the trash heap of history, didn’t magically become safe in 223 chambers.

"Violence, naked force, has settled more issues in history than has any other factor.” Robert A. Heinlein

“You may beat me, but you will never win.” sigmonkey-2020

“A single round of buckshot to the torso almost always results in an immediate change of behavior.” Chris Baker
September 08, 2022, 02:28 PM
I was obviously being deliberately obtuse when I suggested that M193 ammunition suddenly became safe to shoot in 223 Remington chambers when M855 became the “official” NATO cartridge, and didn’t think for a moment that anyone would interpret it differently. What the careful person will say is that any ammunition designated as 5.56×45mm should normally be avoided in 223 chambers, without any reference to the NATO designation. “Shoot only ammunition that matches the chamber designation of your firearm (mostly),” is one of the many firearms safety rules that shooters should keep in mind.

I did, however, learn something with the discussion, and now I will be careful to never again refer to “5.56 NATO” unless it’s the actually the properly-designated round. And now that I know the difference, it will be something else to annoy me when someone else uses it improperly along with the myriad other terms that shooters use incorrectly.
So thanks.
I believe. Roll Eyes