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

Boltgun

Boltgun

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Folks,

As I have seen this show up regularly, and people on both sides of the coin continue to argue it, I am making this a sticky for those who want to refer to the governing body of the ammunition industry. That is the Sporting Arms and Ammunition Manufacturing Institute also referred to as SAAMI.

Here is a comparion of the .223 Remington versus 5.56 x 45mm NATO chambers:

556cham.gif


Further to that, this is a link to the unsafe arms and ammunition combination pages:

http://www.saami.org/specifications...1-Unsafe_Arms_and_Ammunition_Combinations.pdf

I hope this helps those that are not sure.

Boltgun
 
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Interesting that SAAMI deems 9mm parabelum v. 9mm NATO and .223 v. 5.56mm NATO unsafe combinations but make no mention of 308 Winchester v. 7.62mm NATO.....

I've never seen a service pistol or sub-gun marked 9mm NATO...
 
I'm still a little confused here.

Is it safe to use .223 Rem in a rifle chambered for 5.56 NATO ammo?

I know that 5.56 NATO shouldn't be used in a rifle chambered for .223 Rem.
 
shredder said:
I'm still a little confused here.

Is it safe to use .223 Rem in a rifle chambered for 5.56 NATO ammo?

I know that 5.56 NATO shouldn't be used in a rifle chambered for .223 Rem.
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I agree. Could it be possible to put up a moron-proof version of this?
 
From what I remember military rifles designated for NATO ammunition can use the NATO ammo and their civilian counterpart but the opposite is NOT true (5.56 VS .223 and 7.62 VS .308).

IE You can fire a .223 in a NATO 5.56 safely, but you can not fire a nato round in a civilian chambered gun (you cant fire a 5.56 in a .223). The nato round is slightly larger, .224 i believe, so the gun could explode.

As the civilian ammo is ever so slightly smaller then the nato ammo there is a small loss of accuracy when firing .223 in a 5.56 Nato chambered gun.
 
beltfed said:
I've never seen a service pistol or sub-gun marked 9mm NATO...
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They probably mean hot carbine loads like British 2Z. But they are making fools of themselves for pretending there is a NATO standard for 9mm, thus calling their authority into question. A little truth table showing questionable combinations would be the thing here, for simple folk like me.
 
beltfed said:
Interesting that SAAMI deems 9mm parabelum v. 9mm NATO and .223 v. 5.56mm NATO unsafe combinations but make no mention of 308 Winchester v. 7.62mm NATO.....

I've never seen a service pistol or sub-gun marked 9mm NATO...
Click to expand...

Because 7.62 NATO is good-to-go in a .308.
 
I'm pretty sure they're just refering to the higher pressure 9mm nato rounds. They're pretty much 9mm +P+. Most newer guns should be fine with them though.


beltfed said:
Interesting that SAAMI deems 9mm parabelum v. 9mm NATO and .223 v. 5.56mm NATO unsafe combinations but make no mention of 308 Winchester v. 7.62mm NATO.....

I've never seen a service pistol or sub-gun marked 9mm NATO...
Click to expand...
 
Remington advertises their 7615 223 pumps as being able to fire both rounds. Have they changed the chamber to a happy medium for both?
 
marlin said:
Remington advertises their 7615 223 pumps as being able to fire both rounds. Have they changed the chamber to a happy medium for both?
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Might have something to do with the gun not being able to be labled 5.56 eventhough they can still fire it. We all know 5.56 is for going on rampages at malls whilst a 223 could never do that.
 
marlin said:
Remington advertises their 7615 223 pumps as being able to fire both rounds. Have they changed the chamber to a happy medium for both?
Click to expand...

Many guns are chambered to be safe for both 5.56 and .223.
I believe this is basically a 5.56 chamber, which isn't perfect for .223, but it's close enough that it isn't really an issue.
 
.223 Remington ammunition uses a .224" diameter bullet, just as 5.56 does. The 5.56 does NOT use a larger diameter bullet.
The problem with .223 and 5.56 is in the slight difference in chamber throating specifications. Look at the diagrams in the first post in this thread. It is theoretically possible for an interference fit if a 5.56 round is chambered in a .223 chamber. In practice I am unaware of any mishaps resulting from 5.56 ammuntion being fired in a factory spec. .223 chamber.
Sometimes you will see reference to the different presssure specs. for .223 and 5.56. This is comapring apples and oranges. One set of numbers is derived from crusher gauges, in CUPs, the other from strain gauges in PSI. The point at which the pressures are measured is different as well.
NATO 7.62 projectiles tend to be slightly smaller in diameter than civilian .308 bullets. Barrels intended for competitive target shooting with NATO ball were often made deliberately undersized, for better results; groove diameter could be as tight as .3065", rather than the nominal .308".
 
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