# NO-NO here is Remingtons words shooting 5.56 out of .223



## piratebob64 (Nov 11, 2013)

I done posts a few times about this issue. With the rise and popularity of the 5.56 and .223 ammo and guns being used for hunting everyone needs to know this! 

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Per SAAMI specifications: The 5.56 and 223 Remington cartridges are similar, but the chambers of the guns and test barrels they are evaluated in are different. One of the key differences is the length of the throat or leade on the 5.56 chamber compared to the 223 Remington. It’s almost twice as long in the 5.56 chamber versus the 223 Remington chamber.
Typically, the 5.56 round is loaded to a higher velocity and pressure level than the 223 Remington.
Firing the 5.56 round in a 223 Remington chamber with the shorter leade can dramatically increase chamber pressures.
Therefore, we recommend against firing the 5.56 round in a 223 chamber, unless the gun is marked with both cartridge designations such as our Model 7615 Patrol Rifle.


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## wareagle700 (Nov 11, 2013)

Ask Remington why their .223 chambers have just as much throat as a 5.56 chamber.

Remington guns are made to be safe to fire anything you can close the bolt on.

Glad they know the difference between the cartridges though.


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## GoldDot40 (Nov 11, 2013)

wareagle700 said:


> Ask Remington why their .223 chambers have just as much throat as a 5.56 chamber.
> 
> Remington guns are made to be safe to fire anything you can close the bolt on.
> 
> Glad they know the difference between the cartridges though.



A .223 chambered rifle will fire a 5.56 round just fine, I don't believe anyone is disputing that. The main concern is about doing it regularly....which is NOT a good idea.


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## T-N-T (Nov 11, 2013)

I have read that you can throw 223 into a "marked" 5.56 gun.
Not advisable to throw 5.56 into a "marked" 223 gun.   For this very reason.   
Also on a side note-
7.62 nato in 308 ok
308 ammo in 7.62 gun not OK same reasoning with pressures


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## Bobby Jackson (Nov 11, 2013)

TopherAndTick said:


> I have read that you can throw 223 into a "marked" 5.56 gun.
> Not advisable to throw 5.56 into a "marked" 223 gun.   For this very reason.
> Also on a side note-
> 7.62 nato in 308 ok
> 308 ammo in 7.62 gun not OK same reasoning with pressures




umm..wouldn't those last 2 be reversed?


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## ASH556 (Nov 11, 2013)

Bobby Jackson said:


> umm..wouldn't those last 2 be reversed?



Nope....308 win is hotter than 7.62x51 nato.  It's backwards from the .223/5.56 thing.


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## T-N-T (Nov 11, 2013)

ASH556 said:


> Nope....308 win is hotter than 7.62x51 nato.  It's backwards from the .223/5.56 thing.



Yep.  And Im only about a week old to the AR community.   But I have been reading A LOT


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## mike bell (Nov 11, 2013)

.308 in a 7.62 ?   

Had to double check my .308 Remington r25...ITS .308 Win. chamber.... so Im good to go.


> Safe chamber headspace for the .308 Winchester cartidge is between 1.6300 and 1.6340 inches. The equivalent minimum and maximum values for 7.62x51mm NATO chambers are 1.6355 and 1.6405 inches.




But I hope my 3gun AR is 5.56 cause Ive been shooting 5.56 military ball ammo.


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## B Man (Nov 11, 2013)

mike bell said:


> .308 in a 7.62 ?
> 
> Had to double check my .308 Remington r25...ITS .308 Win. chamber.... so Im good to go.
> 
> ...



If its 223 Wylde chamber you are ok to shoot 5.56 ammo.


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## TrailBlazinMan (Nov 12, 2013)

adding confusion, some of the .223 chambers are cut with a deeper throat just in case the end user throws a 5.56 in it, but not all. 

Know your chamber and what you can feed.


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## ASH556 (Nov 12, 2013)

Let's make it even worse:  a lot of the barrels marked "5.56" from some of the "affordable" manufacturers are actually .223.  Symptoms are typically poor feeding, poor extraction, and popped primers.  If you have a rifle that is continually popping primers, that is an indication of overpressure, and you should stop using it until you have your chamber checked/reamed.  Also bear in mind that the more fouled your chamber becomes, the tighter it gets, so a gun that is on the tight side when clean can become dangerously tight when dirty.


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## Bobby Jackson (Nov 12, 2013)

ASH556 said:


> Nope....308 win is hotter than 7.62x51 nato.  It's backwards from the .223/5.56 thing.



hmm..Good to know since I recently bought a .308 bolt


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## The Longhunter (Nov 12, 2013)

piratebob64 said:


> I done posts a few times about this issue. With the rise and popularity of the 5.56 and .223 ammo and guns being used for hunting everyone needs to know this!
> 
> _____________________________________________
> Per SAAMI specifications:
> Typically, the 5.56 round is loaded to a higher velocity and pressure level than the 223 Remington.




Well, without getting into the leade thing, some one at REM doesn't know what they are talking about, because the standards for the pressure levels (thus the velocities) are essentially the same.

As long as a load is within maximum limits, the pressure/velocity shouldn't make a difference.  

FWIW, if someone actually looks at the CIP standard for NATO loads and which uses a different method for measuring chamber pressure, they will find that the pressures (and velocities) are pretty much the same as standard American sporting loads.


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## wareagle700 (Nov 12, 2013)

The Longhunter said:


> Well, without getting into the leade thing, some one at REM doesn't know what they are talking about, because the standards for the pressure levels (thus the velocities) are essentially the same.
> 
> As long as a load is within maximum limits, the pressure/velocity shouldn't make a difference.
> 
> FWIW, if someone actually looks at the CIP standard for NATO loads and which uses a different method for measuring chamber pressure, they will find that the pressures (and velocities) are pretty much the same as standard American sporting loads.




They may have similar pressures and velocities but that does not make them interchangeable in all rifles.

Those pressures are developed with rounds fired in the correct chambers. The difference in throat/leade can and does make a difference in pressure.


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## Bobby Jackson (Nov 12, 2013)

I wish you guys could make up yur minds..i wanna go shoot..
which is it?


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## ASH556 (Nov 12, 2013)

Bobby Jackson said:


> I wish you guys could make up yur minds..i wanna go shoot..
> which is it?



.223 in 5.56 chamber = good
5.56 in .223 chamber = no good

7.62x51 nato in .308 chamber = good
.308 in 7.62x51 nato chamber = no good


In 22 cal, the Nato pressure is higher.  In 30 cal, the commercial pressure is higher.
The real world application for this comes more in shooting semi's than bolts.  Bolt actions typically have a stronger lockup design so even if you do over-pressure the chamber, the bolt action can usually handle it a little more.

*These are general safety guidelines...it doesn't mean if you do it one time that your gun is going to suddenly blow up.*


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## The Longhunter (Nov 12, 2013)

wareagle700 said:


> They may have similar pressures and velocities but that does not make them interchangeable in all rifles.
> 
> Those pressures are developed with rounds fired in the correct chambers. The difference in throat/leade can and does make a difference in pressure.



I'm not saying that they are interchangeable, but suggesting that it is pretty irresponsible for a supposed authority like REM to make a blanket statement that is wrong.


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## wareagle700 (Nov 12, 2013)

The Longhunter said:


> I'm not saying that they are interchangeable, but suggesting that it is pretty irresponsible for a supposed authority like REM to make a blanket statement that is wrong.



I don't see where they said that.


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## bullethead (Nov 12, 2013)

http://www.humanevents.com/2011/02/15/223-remington-vs-556-nato-what-you-dont-know-could-hurt-you/


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## watermedic (Nov 12, 2013)

The barrel needs to have the 5.56 NATO designation on it.
	

	
	
		
		

		
			





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## RamblinWreck (Nov 12, 2013)

This again???? LOL The throat diff isn't an issue with any mag-length NATO ammo, sorry. (COL <= 2.250"). Unless you are trying to shoot long-loaded USAMU 80 GN Sierra loads in your older tight benchrest chamber 1-12 twist bolt-action varmint rifle, this is a non-issue. There is nothing sold off the shelf that will hurt your AR-platform rifle. If you have extraction issues shooting M855 NATO ball in an AR, you have a poorly chambered AR. This is from guys who know, who make the ammo and guns for the best shooters in the nation, the USAMU.

PS Rem is just playing CMA like all the rest in our overly-litigious society.

EDIT: as for NATO 7.62x51mm, the pressure diff is because of the op rod in an M14, which can only stand so much port pressure before it bends.


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## bullethead (Nov 12, 2013)

RamblinWreck said:


> This again???? LOL The throat diff isn't an issue with any mag-length NATO ammo, sorry. (COL <= 2.250"). Unless you are trying to shoot long-loaded USAMU 80 GN Sierra loads in your older tight benchrest chamber 1-12 twist bolt-action varmint rifle, this is a non-issue. There is nothing sold off the shelf that will hurt your AR-platform rifle. If you have extraction issues shooting M855 NATO ball in an AR, you have a poorly chambered AR. This is from guys who know, who make the ammo and guns for the best shooters in the nation, the USAMU.
> 
> PS Rem is just playing CMA like all the rest in our overly-litigious society.
> 
> EDIT: as for NATO 7.62x51mm, the pressure diff is because of the op rod in an M14, which can only stand so much port pressure before it bends.



I don't think people are worried about hurting their AR as much as firing Military ammo out of a bolt action etc. I have a Savage 340 chambered in .223 that I ruined many years ago when I was in my teens. I shot a lot of military ammunition through it and now fired ammo will not extract. The chamber was ruined, actually oblong ever so slightly. A gunsmith told me that back in the mid 1980's when I started to have extraction problems. Fired brass is out of spec.


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## T-N-T (Nov 12, 2013)

bullethead said:


> I don't think people are worried about hurting their AR as much as firing Military ammo out of a bolt action etc. I have a Savage 340 chambered in .223 that I ruined many years ago when I was in my teens. I shot a lot of military ammunition through it and now fired ammo will not extract. The chamber was ruined, actually oblong ever so slightly. A gunsmith told me that back in the mid 1980's when I started to have extraction problems. Fired brass is out of spec.



This isnt going to go well...  A guy has just given proof of a problem to which I am sure some one will be along very shortly to discredit.


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## wareagle700 (Nov 12, 2013)

What matters is that there *is* a difference in pressure between the two cartridges when fired in the same chamber. It is highly unlikely that either will damage a modern firearm with a properly chambered and headspaced barrel. But, there is a difference in pressures and people need to be aware of it when making decisions on rifles and ammo.

Ex:
If you have a tight chambered .223 match barrel, I would not be putting Mk262 through it on a regular basis. Not that it will explode, but it may cause premature wear or broken parts over time.


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## The Longhunter (Nov 12, 2013)

wareagle700 said:


> I don't see where they said that.



You must not have read the REM press release very closely, then.



> Typically, the 5.56 round is loaded to a higher velocity and pressure level than the 223 Remington.



That is wrong.


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## DYI hunting (Nov 12, 2013)

I wouldn't worry too much but I personally avoid shooting hotter 5.56 in a .223 spec barrel just as I would avoid shooting hotter .308 in a 7.62 only barrel.  I have never seen a catastrophic failure in any .223 or 7.62 only chamber when shooting hotter factory loaded 5.56 or .308 ammo.  I would worry about long term using causing some minor issues like a broke bolt lug, throat erosion, etc.


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## RamblinWreck (Nov 13, 2013)

I'll do my best to be clear: 

The only problems that ever occur 5,56mm NATO vs .223 Rem is shooting ammo that was designed for a Eugene Stoner-designed gas gun (i.e, an M16/AR15) in a sporting bolt action of typical .223 Rem vintage, such as the prev poster's bolt action, which is not a 5.56mm Stoner gas gun, is it? This has less to do with the throat length than it does with the gun being a Stoner gas gun of caliber 5,56 NATO and having a higher pressure spec (62366 psi) vs a typical .223 Rem (55000 psi, SAMMI) bolt action sporter. They are simply two COMPLETELY different guns, and two different cartridges, albeit dimensionally the same. Look at the history of the calibers; understand it. The Remington verbage cited means nothing. There is a real pressure diff between calibers, if you say there isn't, you are ignorant of the facts. 

For arguments sake, if one had a nice vintage Win M70 or Rem 700 bolt in .223, it probably has a 1-14" or 1-12" twist intended for light varmint bullets below 50 GN, and won't stabilize a 62 NATO, nor a Sierra 77. So why would you shoot that stuff anyway? It will be all over your target and the bolt lift will be sticky from the over-pressure. So stop and use the right ammo, or get a barrel chambered for 5,56 NATO with a 1-7" or 1-8 twist, like some police/tactical models already do.

On the other hand, if you have an AR gas gun that won't shoot NATO ammo, use the barrel for a tomato stake and get a new proper barrel because yours is shi-ite.


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## wareagle700 (Nov 13, 2013)

The Longhunter said:


> You must not have read the REM press release very closely, then.
> 
> 
> 
> That is wrong.



If both are fired from a .223 chamber that is actually correct. I read it as if they were assuming that were the case since that was the question presented to them.


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## bullethead (Nov 13, 2013)

More reading on it...
http://www.rifleshootermag.com/2012/02/02/5-56-and-223-are-they-different/


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## Bonaire-Dave (Nov 13, 2013)

so does anyone know how many firearms have been damaged.  I would think in an emergency no one would care. Most .223's I've seen are bolt action and most AR style are marked 5.56.  Dave


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## wareagle700 (Nov 13, 2013)

Blairsville-Dave said:


> so does anyone know how many firearms have been damaged.  I would think in an emergency no one would care. Most .223's I've seen are bolt action and most AR style are marked 5.56.  Dave



Yep. That is why its pretty much not a big deal.


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## 7MAGMIKE (Nov 15, 2013)

bullethead said:


> More reading on it...
> http://www.rifleshootermag.com/2012/02/02/5-56-and-223-are-they-different/


 
After reading this article last year a friend of mine bought the chamber gauge from Michiguns and found his 5.56 marked Bushmaster was not 5.56 he also bought the reamer from Michiguns and reamed up his chamber.  I checked my Bushmaster and found the same condition in my 5.56 marked barrel and reamed mine also.  Accuracy is as well as ever and I know my chamber for sure is 5.56.


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