.223 remington versus 5.56 x 45 mm NATO - is it safe to interchange???

Blastattack said:
To sum it up:

.223 Rem=5.56x45
.308 Win=7.62x51

If someone tells you otherwise they're an idiot. Especially so if they start talking pressures.
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Better not tell Western Powders that then because just for a for instance they list .223 max loads quite a bit lower than the same bullets used in 5.56 max loads.
For example I load .223 brass for use in a 5.56 gun using 26.1gr of Ramshot Tac which is a middle-ish load for a 5.56 but 3/10 over the maximum for a .223.
 
Blastattack said:
To sum it up:

.223 Rem=5.56x45
.308 Win=7.62x51

If someone tells you otherwise they're an idiot. Especially so if they start talking pressures.
Click to expand...

To add to the confusion usually NATO 5.56 and civilian .308 is loaded hotter then the civilian .223 and the NATO 7.62.
 
I’d never denigrate anyone for thinking it’s not safe to use either 308 Winchester or 7.62 NATO in the same rifle, but for those of you who believe that it’s not safe to use either 308 Winchester or 7.62 NATO in the same rifle, denigrate means to put someone down.

Same goes for 223 Rem and 5.56 NATO.
 
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I have been all thru this with a retired Marine Armorer and it seems the only real difference aside from the small variations in headspace is the tolerances on the chambers and that military rounds are not rated to SAAMI spec. Powders are different too and there is a large variance in loads so you MIGHT get a hot one, you may never. Not the kind of surprise I care for. I have a LE rated barrel on my AR that is rated for 5.56. Of necessity because it has to feed everything even dirty the tolerances on mil chambers are a tad on the sloppy side. Be a real beatch to have your chamber jam up in the middle of a firefight just cuz its loaded up with crap. Best to stick with the rule that its ok to run civvy ammo in a military barrel but not the other way around. I have seen guys on the range that bought an AR with a 223 barrel on it and were sold 5.56 ammo for it. Every 4th or 5th round would not go all the way in and the dumbass was slamming the charge handle to get it to lock up. The cases were sticking out about 1/8in. I have never seen a slamfire and hope to never. Yeah I know the cases are pretty much the same on the outside but that changes when you look inside..
 
I'd love to know how many of the guys on either side of this fence are "experienced" hand loaders.

My guess is that 90 percent of those who say they are not interchangable also don't hand load.
Further I would guess that of those who say they are interchangeable, 90 percent very experienced hand loaders.
 
BadAsMo said:
I'd love to know how many of the guys on either side of this fence are "experienced" hand loaders.

My guess is that 90 percent of those who say they are not interchangable also don't hand load.
Further I would guess that of those who say they are interchangeable, 90 percent very experienced hand loaders.
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Couldn't agree more. Loaded many rounds for both AR10 & 15 without any problems. Actually my LMT 308 chamber is a 308 match chamber according to one of the engineers I spoke to at LMT . So if the military is using 762x51 NATO ammo threw these rifles it must be safe
 
I can't believe this topic has garnered 21 pages of back and forth debate! That is crazy! The ambiguity here lies in the fact that the chamber tolerances for 5.56mm NATO and .223 are different, but overlapping, as are the tolerances for ammo. That means that, when looking at the outer limits of the tolerance stackup, you can fit .223 in a 5.56mm chamber, but not the other way around. However, at the opposite extreme of comparison, where the tolerances overlap, you could go either way without issue. It comes down entirely to where in the tolerances your chamber sit and the tolerance on your ammunition.

Generally it is simpler to just go with the fact that any .223 ammo that meets the tolerance spec is guaranteed to fit in either a .223 or 5.56mm chamber, but 5.56mm that meets the tolerance spec is only guaranteed to be safe in a 5.56mm chamber. Of course, people need to understand that this is simply the "safe and simple" way of looking at it and should by no means limit someone who has the time to ensure that their particular chamber will shoot their desired ammo.

-J
 
The confusions also lies with importation, some barrels like the Tavor are stamped .223 as it's easier to import.

Yet it's technically a 5.56 barrel and IWI states you can unload all the 5.56 you want down it.

Makes me wonder how many other barrels have had this happen to them?
 
tavtastic said:
The confusions also lies with importation, some barrels like the Tavor are stamped .223 as it's easier to import.

Yet it's technically a 5.56 barrel and IWI states you can unload all the 5.56 you want down it.

Makes me wonder how many other barrels have had this happen to them?
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AS is the Troy PAR
 
to add some confusion i shot during my army time i shot some israelis ammo some were written 5.56NATO some others 223 rem ... exactly the same and i do know if it was due to importation reason it was at the end of the 80s .... it was in a FAMAS and no difference in sighting on target ...
 
And the answer is...?

So it seems there is no simple answer to this seemingly simple question. Some members are saying don't use one in the other, while others contend the two are interchangeable.
And here I sit with an AR on my lap that has "CAL.223" stamped on the lower, and a case of 5.56 ball ammo beside it.
 
Most ammo labeled 556 isnt...

True 556 will be over 3200 fps in a 18" barrel...

Anyone who has ever chronoed american eagle "556" will know its much closer to 3100fps

A good portion of ".223" chambers are horrendously loose, and probably exceed 556 specs

I use whatever after checking for excess pressure signs
 
BadAsMo said:
I'd love to know how many of the guys on either side of this fence are "experienced" hand loaders.

My guess is that 90 percent of those who say they are not interchangable also don't hand load.
Further I would guess that of those who say they are interchangeable, 90 percent very experienced hand loaders.
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Yes, sort of.

PitBull1973 said:
Couldn't agree more. Loaded many rounds for both AR10 & 15 without any problems. Actually my LMT 308 chamber is a 308 match chamber according to one of the engineers I spoke to at LMT . So if the military is using 762x51 NATO ammo threw these rifles it must be safe
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Me too.

Sqr said:
YES it’s ok...end of story.
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Again, not always; see my post here: https://www.canadiangunnutz.com/for...t-the-same?p=14646598&viewfull=1#post14646598
 
Hahaha This is hilarious. Amazing the amount of guys who shoot tons but have no clue about reloading/pressure/chamber dementions. Is there a difference in chambers, yes. Could this cause a problem, yes. Does it? Pretty much never. If you hand load none of this matters. End of story.
 
Lets not forget that for a few years, the US wouldn't allow "military" barrels to be exported (gotta love ITAR), so many makers simply stamped them 223. Add in are all of the hybrid chambers - mostly longer necks and either longer or shorter throats by 1, 2 or 3 ten thousandths and you have a real mess.
 
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