# 5.56 / .223 Ammunition Question



## Dogrman1 (Jan 13, 2009)

Is there any difference between a 5.56 Ball and .233 ammo? Casing length or grains of powder for factory loads in particular?? i know hand loads will very from loadre to loader. The reason I ask is I have heard it both ways that there is and that there is not any difference? I don't have any concrete evidence to argue the point either way, so I am asking for some input for anyone. Thanks Mark!


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## Ron Gilmore (Jan 7, 2003)

I will dig up the info, but if the gun is not listed as being a 5.56 cal it is not recommended to use the military loaded ammo in it. I do not remember why, I do believe it had to do with powder type and pressures.


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## Savage260 (Oct 21, 2007)

The 5.56 chamber and the .223 chamber are different and the ammo is slightly different also. Google 5.56 vs .223 and you will find tons of info on this. 5.56 can shoot .223, but it is not recommended to shoot 5.56 out of a .223.


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## southdakbearfan (Oct 11, 2004)

From wikipedia

While the 5.56mm NATO and .223 Remington cartridges and chamberings are very similar, they are not identical.

Military cases are generally made from thicker brass than commercial cases; this reduces the powder capacity (an important consideration for handloaders[4]), and the NATO specification allows a higher chamber pressure. NATO EPVAT test barrels made for 5.56mm NATO measure chamber pressure at the case mouth, as opposed to the location used by the United States civil standards organization SAAMI. The piezoelectric sensors or transducers NATO and SAAMI use to conduct the actual pressure measurements also differ. This difference in measurement method accounts for upwards of 137.9 MPa (20,000 psi) difference in pressure measurements. This means the NATO EPVAT maximum service pressure of 430 MPa (62,366 psi) for 5.56mm NATO, is reduced by SAAMI to 379.21 MPa (55,000 psi) for .223 Remington.[5] In contrast to SAAMI, the other main civil standards organization C.I.P. defines the maximum service and proof test pressures of the .223 Remington cartridge equal to the 5.56mm NATO.

The 5.56mm NATO chambering, known as a NATO or mil-spec chamber, has 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 Remington chambering, known as 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 (Rock River Arms)[6] or the Armalite chamber, which are designed to handle both 5.56mm NATO and .223 Remington equally well. The dimensions and leade of the .223 Remington minimum C.I.P. chamber also differ from the 5.56mm NATO chamber specification.

Using commercial .223 Remington cartridges in a 5.56mm NATO chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223 Remington chambered gun due to the longer leade.[7] Using 5.56mm NATO mil-spec cartridges (such as the M855) in a .223 Remington chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[8] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56mm NATO, such as many commercial AR-15 variants and the Ruger Mini-14, 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 5.56mm NATO ammunition.[9]


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