.223/5.56....difference

[DemonOfTheFall]

From wikipedia....

While the 5.56 mm and .223 cartridges are very similar, they are not identical. Military cases are made from thicker brass than commercial cases, which reduces the powder capacity (an important consideration for handloaders), and the NATO specification allows a higher chamber pressure. Test barrels made for 5.56 mm NATO measure chamber pressure at the case mouth, as opposed to the SAAMI location. This difference accounts for upwards of 20,000+ psi difference in pressure measurements. That means that advertised pressure of 58,000 psi for 5.56 mm NATO, is around 78,000 psi tested in .223 Rem test barrels (SAAMI .223 Rem Proof MAP is 78,500 psi so every 5.56 mm round fired is a proof load, very dangerous). The 5.56 mm chambering, known as a NATO or mil-spec chambers, have a longer leade, which is the distance between the mouth of the cartridge and the point at which the rifling engages the bullet. The .223 chambering, known as the "SAAMI chamber", is allowed to have a shorter leade, and is only required to be proof tested to the lower SAAMI chamber pressure. To address these issues, various proprietary chambers exist, such as the Wylde chamber[2] or the Armalite chamber, which are designed to handle both 5.56 mm and .223 equally well.


These 5.56x45mm NATO cartridges are identical in appearance to .223 Remington. They are, however, not completely interchangeable.
Using commercial .223 cartridges in a 5.56-chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223-chambered gun due to the excessive lead. [3] Using 5.56 mil-spec cartridges (such as the M855) in a .223-chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[4] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56 mm, such as many commercial AR-15 variants and the Ruger Mini-14[5], but 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 mm ammunition.

Something to consider? Bullsh#t? Seems like the distinction is thrown around pretty casually. Can we as civilians even buy real milspec NATO rounds? Anyone shoot alot of 5.56 and notice a difference, performance-wise?

[Lycanthrope]

Yes, you can buy NATO rounds. Yes, the pressure is significantly different and shooting hot 5.56 rounds out of a match/tight .223 chamber in an AR15 can bite you.

Here is a larger resource:

http://www.ammo-oracle.com/


Lycanbelieveitthrope

[40twist]

Kewl , I guess the guy at the gun store actually knew what he was talking about when he told me to go 5.56 and not 223 so I "could" shoot both. Actually there is a short article of the same subject in the new guns&ammo mag

[bert304]

There is no problem shooting 5.56 or .223 out of a stock AR-15 it is when you get a custom or after market barrel that you have to be careful. The stock AR-15 has a 5.56 chamber unless it states .223 Remington caliber. I shoot 5.56 and handload 5.56 cases, The only problem I have is you have to watch the capicaties because of the thicker brass. Smaller powders work better because they fill the case tighter. For example I was using RL15 at 23.5 grains, it was filling the entire case to the middle of the neck. Then I switched to BLC(2) and I went to 26.5 grains. This load is to the bottom of the neck and filled the case better.

[righteousbarbarian]

do you know if 5.56 would be OK to shoot out of my Stag Arms AR15?

[addicted2freedom]

I was just researching the same thing. Unfortunately, after I had put in an order for 1,000 rounds of 5.56 and finding out that my rifle manual specifies .223.

Owners of my rifle say 5.56 is fine to use as does the seller. I'm awaiting word from the manufacturer now.

It's difficult being a noob. Haha!

[bert304]

do you know if 5.56 would be OK to shoot out of my Stag Arms AR15?

Yes there is no problem I have a Stag AR-15 also and it fires either just fine. On firearms that are .223 caliber just make sure it does not say chambered for .223 then you can not shoot 5.56mm.

The Evil Black Rifles(AR-15s) are chambered for the Military chamber of 5.56 X 45mm so you can shoot either 5.56 or .223.

When you handload for these rifles you need to use the .223 info out of a reloading book for 55 grain bullets. Most Reloading books show only 69 and 75 grain bullets for 5.56mm. Just set the length to the one specified in the book as O.A.L. You also need to crimp the cases.

Check the chamber for the correct caliber it will say 5.56mm or it will say .223 Remington.

[bert304]

I was just researching the same thing. Unfortunately, after I had put in an order for 1,000 rounds of 5.56 and finding out that my rifle manual specifies .223.

Owners of my rifle say 5.56 is fine to use as does the seller. I'm awaiting word from the manufacturer now.

It's difficult being a noob. Haha!

What type of rifle is it? What does it say on the barrel?

[Warners Surplus]

Yes there is no problem I have a Stag AR-15 also and it fires either just fine. On firearms that are .223 caliber just make sure it does not say chambered for .223 then you can not shoot 5.56mm.

The Evil Black Rifles(AR-15s) are chambered for the Military chamber of 5.56 X 45mm so you can shoot either 5.56 or .223.

When you handload for these rifles you need to use the .223 info out of a reloading book for 55 grain bullets. Most Reloading books show only 69 and 75 grain bullets for 5.56mm. Just set the length to the one specified in the book as O.A.L. You also need to crimp the cases.

Check the chamber for the correct caliber it will say 5.56mm or it will say .223 Remington.

bert304,
not ALL evil black rifles are chambered in 5.56 or Wildey. if you are running a factory ie: Bushmaster,Colt,Armalite etc etc just check the receiver if it says 223/5.56 or 5.56/223 then it is chambered in either 5.56 or Wildey. If it says 223 (quite a few Colts made for LE use) then it is 223 period. The usual result of shooting 5.56 ammo in a 223 chambered AR. is blow primers and a jammed rifle but it could get worse. If you are running a custom built or home built rifle then definately check the barrel MOST AR barrel manufaturers stamp the barrel ahead of the handgaurds so you can be sure but some are stamped UNDER the handgaurds.


Rich W.

[addicted2freedom]

What type of rifle is it? What does it say on the barrel?

It's a POF-415. I'm not sure what it says on the barrel, but I can check when I get home.

The manual states "The POF Weapons System is chambered in .223 Rem. (5.56x45mm) and utilize standard AR- 15 / M16 / M4 style magazines." And I just noticed the website says "the barrel is chambered for "5.56 mm Nato (.223 Cal.)".

I assume that means it will take either, but, as a gun noob, I don't really want to rely on assumptions. Maybe, I'm being too cautious and paranoid? HAH!