Hey everyone. I don't know if this has been asked before, but I did do a couple searches and found nothing. I have some x-tac 55gr 556 ammo that does not have the NATO stamp on the case. I was under the impression that all 556 was nato, now I'm not sure. So is there actually just 223 and 556 nato, or is there 223, 556x45, and 556x45 nato?
is all 556 nato?
- Thread starter cz93
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NWcityguy2
Member
If the box says 5.56 then assume it is 5.56. There is no difference between the brass used for 5.56 ammo and the brass used for 223 Remington ammo. The head stamp is strictly for identification purposes.
NWcityguy2
Member
Consider it 5.56 pressure then. Are you aware of the difference between 5.56 and 223 ammo, along with 5.56 and 223 chambers?
lysanderxiii
Member
No. All 5.56mm ammunition is not NATO standard.
Cartridge, 5.56mm, Ball, M193 is not NATO standard.
Cartridge, 5.56mm, Ball, M855 is NATO standard.
Similarly M196 tracer is not, M856 Tracer is.
I'll let you google the differences between M855 and M193.
As to the pressure...
It is not so much the propellant charge, as the chamber. SAAMI chambers have shorter throats, this makes military ammunition exhibit higher pressures in SAAMI chambers.
Military ammunition, when tested in military test barrels, have similar pressures to commercial ammunition, tested in commercial test barrels.
In the AR-15 world, there are almost no barrel manufacturers that offer true SAAMI spec chambers, they are all Military or longer throated hybrids that allow for use safe use of military ammunition.
Cartridge, 5.56mm, Ball, M193 is not NATO standard.
Cartridge, 5.56mm, Ball, M855 is NATO standard.
Similarly M196 tracer is not, M856 Tracer is.
I'll let you google the differences between M855 and M193.
As to the pressure...
It is not so much the propellant charge, as the chamber. SAAMI chambers have shorter throats, this makes military ammunition exhibit higher pressures in SAAMI chambers.
Military ammunition, when tested in military test barrels, have similar pressures to commercial ammunition, tested in commercial test barrels.
In the AR-15 world, there are almost no barrel manufacturers that offer true SAAMI spec chambers, they are all Military or longer throated hybrids that allow for use safe use of military ammunition.
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Art Eatman
Moderator In Memoriam
Specs for issue ammo in NATO vary from time to time. Some ammo may have been issued as a standard in the past but now has been superceded by some change in specs and is no longer current issue.
Driftertank
Member
Many COMMERCIALLY LOADED ammunitions which are labelled 5.56 are "hotter" than loads labelled .223, at least in the same company. PMC X-tac XP193 55gr produces velocities at or near 3100fps from my Criterion-barreled carbine. PMC Bronze .223 55gr produces around 2800fps. I have heard Black Hills Match 77gr OTM comes in both "red box" and "blue box," and IIRC, the red box is a 5.56 load that nearly duplicates Mk262 ballistics... But I'm going from memory, so feel free to correct me.
As an aside, I like the X-tac ammo. It's fairly accurate from my rifle and leaves some decent reload able brass.
As an aside, I like the X-tac ammo. It's fairly accurate from my rifle and leaves some decent reload able brass.
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