# Rifles stamped .223



## BigChessie (Mar 12, 2005)

With the big rush to purchase the "Black Evil Rifle", I have grown tired of debating a certain fact with several people. "NO" you should NOT shoot 5.56 out of a weapon chambered for .223. They ARE NOT the same rounds!



http://www.saami.org/Unsafe_Combinations.cfm

Scan down to .223


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## PapawSmith (Feb 13, 2007)

Nice resource.
Another popular question that is seldom answered twice the same way is the .308 Winchester - 7.62x51 (.308 NATO) one. Same thing NOT the same loads. I'm suprised that that one was not listed there.


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## littleking (Jun 25, 2005)

why not just say:

before you shoot .223 out of 5.56 or vice versa: the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56/.223


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## littleking (Jun 25, 2005)

PapawSmith said:


> Nice resource.
> Another popular question that is seldom answered twice the same way is the .308 Winchester - 7.62x51 (.308 NATO) one. Same thing NOT the same loads. I'm suprised that that one was not listed there.



they are not listed because they are safely interchangeable.


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## BigChessie (Mar 12, 2005)

littleking said:


> why not just say:
> 
> before you shoot .223 out of 5.56 or vice versa: the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56/.223


There is no reason to worry about the .223 coming out of the 5.56. it is the other way around that people need to worry about. Even though I know guys that have done it. I wish I could find a resourse that would explain what can happen if you fire 5.56 into a .223 weapon I have a couple and I am sure I have done it, just becaue I have all kinds of mixed ammo for the AR's. So I am sure some time I have had to grab a round without looking at it and shot it. Of course now I have talked myself out of giving it a try to see what the spent round looks like


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## sam kegg (Jun 23, 2007)

38 cal 357 magnum,,,, same thing? when you go to pro gun thats what they sell you for a 357


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## littleking (Jun 25, 2005)

BigChessie said:


> TI wish I could find a resourse that would explain what can happen if you fire 5.56 into a .223 weapon


some call it automatic spontaneous disassembly...

higher pressures = bad things (exessive wear and tear)

watch for flattened/deformed primers, or powder residue around the primer


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## Orlando (Apr 12, 2004)

littleking said:


> they are not listed because they are safely interchangeable.


They are not safetly interchangeable in all firearms!
http://www.fulton-armory.com/308.htm


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## littleking (Jun 25, 2005)

per sammi and nato, they are considered safely interchangeable


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## BigV (Nov 11, 2004)

sam kegg said:


> 38 cal 357 magnum,,,, same thing? when you go to pro gun thats what they sell you for a 357


If the pistol is chambered in .357 you can safely shoot .38 ammunition in the gun. 
Its cheaper to practice with .38 ammo instead of .357.
If the pistol is chambered in .38, you can not shoot .357 ammunition.


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## Orlando (Apr 12, 2004)

littleking said:


> per sammi and nato, they are considered safely interchangeable


Believe what you want but I know differently. It all has to do with headspace in military chambers. You do not want to fire 308 in a military 7.62 chamber!!!

http://www.surplusrifle.com/shooting2006/308vs762nato/index.asp


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## PapawSmith (Feb 13, 2007)

littleking said:


> per sammi and nato, they are considered safely interchangeable


You indicated in a previous post about the hazards of higher pressure in similar rounds 5.56 and .223 and you say that .308 and 7.62x51 are safely interchangable. I don't believe either Sammi or NATO says so.
Commercially manufactured .308 Winchester loads can carry as much as 30 percent more PSI than NATO 7.62x51 rounds. Commercially made max presure rounds fired from a weak or worn NATO action could cause a real painful problem for the shooter.
The fact of the matter is these rounds are both different in headspace dimensions (which creates a hazard also with reloaded ammo) and max psi. .308 Winchester ammo should not really be fired out of a .308 NATO firearm.


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## littleking (Jun 25, 2005)

it is normally fine to shoot quality 7.62x51 NATO ammo in a gun chambered for the .308 Winchester, NOT 308 Winchester ammo in a gun chambered for the 7.62x51 NATO.

my reply was to why the 308 was not listed... not the 7.62x51. this is because you generally CAN shoot NATO thru a gun chambered for .308 win.

sorry for the confusion


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## CasualFisherman (May 21, 2004)

BigChessie said:


> With the big rush to purchase the "Black Evil Rifle", I have grown tired of debating a certain fact with several people. "NO" you should NOT shoot 5.56 out of a weapon chambered for .223. They ARE NOT the same rounds!
> 
> 
> 
> ...


BigChessie,

You are right that they are not the same load but they are the same cartridge. The 5.56 is the metric designation for the 223 Remington. The military load of 5.56 is just that, a load which has higher pressure potential than SAAMI specs on the 223 Remington. Military rifles have a longer leade (allows greater variance in bullet seating) and the brass is generally thicker (resulting in higher pressure). This 5.56 military load is not commercially available and is loaded strictly for military use with the longer lead and higher pressure requirements in mind. All commercially available "surplus" ammo is loaded to the lower 223 specs. It hasn't been since the 80s from what I can tell that true military loaded ammo was commercially available and that was imported stuff. It is only the combination of a hot cartridge with a short leade that could result in higher pressures and potential danger. You think any sane ammunition manufacturer would commercially sell ammunition that could result in a huge product liability issue? True it is that you would not want to use military loaded ammo and run it through a 223 commercial rifle but good luck getting your hands on a military loaded 5.56 cartridge. It wouldn't be by commercial means that it was acquired. The cartridge dimensions between the two loads are identical.

If you know where you can get true military loaded 5.56MM ammo commercially please share and I will stand corrected.


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## Nikster (Mar 14, 2007)

casualfisherman said:


> bigchessie,
> 
> you are right that they are not the same load but they are the same cartridge. The 5.56 is the metric designation for the 223 remington. The military load of 5.56 is just that, a load which has higher pressure potential than saami specs on the 223 remington. Military rifles have a longer leade (allows greater variance in bullet seating) and the brass is generally thicker (resulting in higher pressure). This 5.56 military load is not commercially available and is loaded strictly for military use with the longer lead and higher pressure requirements in mind. All commercially available "surplus" ammo is loaded to the lower 223 specs. It hasn't been since the 80s from what i can tell that true military loaded ammo was commercially available and that was imported stuff. It is only the combination of a hot cartridge with a short leade that could result in higher pressures and potential danger. You think any sane ammunition manufacturer would commercially sell ammunition that could result in a huge product liability issue? True it is that you would not want to use military loaded ammo and run it through a 223 commercial rifle but good luck getting your hands on a military loaded 5.56 cartridge. It wouldn't be by commercial means that it was acquired. The cartridge dimensions between the two loads are identical.
> 
> If you know where you can get true military loaded 5.56mm ammo commercially please share and i will stand corrected.


*c o r r e c t !*


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## Orlando (Apr 12, 2004)

In the 1950's, the US military adopted the metric system of measurement and uses metric
measurements to describe ammo. However, the US commercial ammo market typically
used the English "caliber" measurements when describing ammo. "Caliber" is a
shorthand way of saying "hundredths (or thousandths) of an inch." For example, a fifty
caliber projectile is approximately fifty one-hundredths (.50) of an inch and a 357 caliber
projectile is approximately three-hundred and fifty-seven thousandths (.357) of an inch.
Dimensionally, 5.56 and .223 ammo are identical, though military 5.56 ammo is
typically loaded to higher pressures and velocities than commercial ammo and may, in
guns with extremely tight "match" .223 chambers, be unsafe to fire.
The chambers for .223 and 5.56 weapons are not the same either. Though the AR15
design provides an extremely strong action, high pressure signs on the brass and primers,
extraction failures and cycling problems may be seen when firing hot 5.56 ammo
in .223-chambered rifles. Military M16s and AR15s from Colt, Bushmaster, FN, DPMS,
and some others, have the M16-spec chamber and should have no trouble firing hot 5.56
ammunition.
Military M16s have slightly more headspace and have a longer throat area, compared to
the SAAMI .223 chamber spec, which was originally designed for bolt-action rifles.
Commercial SAAMI-specification .223 chambers have a much shorter throat or leade
and less freebore than the military chamber. Shooting 5.56 Mil-Spec ammo in a
SAAMI-specification chamber can increase pressure dramatically, up to an additional
15,000 psi or more.
The military chamber is often referred to as a "5.56 NATO" chamber, as that is what is
usually stamped on military barrels. Some commercial AR manufacturers use the tighter
".223" (i.e., SAAMI-spec and often labeled ".223" or ".223 Remington") chamber, which
provides for increased accuracy but, in self-loading rifles, less cycling reliability,
especially with hot-loaded military ammo. A few AR manufacturers use an in-between
chamber spec, such as the Wylde chamber. Many mis-mark their barrels too, which
further complicates things. You can generally tell what sort of chamber you are dealing
with by the markings, if any, on the barrel, but always check with the manufacturer to be sure


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