Why was 223/5.56 annointed?

[Metal god]

Look at any modern reloading manual. You will find separate data for .223 and for 5.56, and the 5.56 data is always hotter at the max end.

I'd say take another look and compare apples to apples . When you look at same bullet and powder . The max charges are about the same . With some 223 having higher charges . Assuming more powder means more pressure they seem to be closer then further apart in the manuals . At least the two I have that have separate loads for 223 and 5.56 ( Hornady & Sierra )

The thing I'm having a hard time believing is nobody from any test facility has put a factory NATO round in a test system that measures CUP . Or a 223 in a system that measures PSI . You would think those test would tell us once and for all if a factory NATO round produces more CUP then a 223 or vise versa .

Am I missing something here . It just seems like it should be relatively simple to figure out if 5.56 ammo is loaded to much higher pressures then 223 . If you test both 223 & 5.56 in both testing methods it should not matter that the tests are different .

You just do a blind test , no names just cartridge A produced xx,xxx CUP , cartridge B produced xx,xxx CUP . Then the same with "ALL" other test methods . Why would that not put this to bed once and for all ?

 

[Brian Pfleuger]

Look at any modern reloading manual. You will find separate data for .223 and for 5.56, and the 5.56 data is always hotter at the max end.

This is incorrect.

If you check Hodgdon's online data, you will see that they make no mention whatsoever of 5.56, seperate or otherwise. You will find, however, that they refer to the cartridges as one and the same in their descriptions of their powders. Specifically, under H335 they say "used for the 5.56 NATO, or 223 Remington as handloaders know it." and under CFE223 they say "in many cartridges such as the 204 Ruger, 223 Remington/5.56mm NATO, 22-250 Remington and the 308 Winchester/7.62mm NATO, "

Note that .308/7.62 are also considered interchangeable by them.

If you check the Lyman 49th, you'll also find that they have no listing of 5.56NATO but on their .223 Remington page the first sentence of the description says "The .223Remington/5.56NATO has become one of the most popular...." and goes on to say "Remington introduced this cartridge to the commercial market in 1964 after it's adoption by the US military as the 5.56 NATO..."

Neither company has any sort of disclaimer of warning and uses the names interchangeably.

It IS however absolutely inarguably true that the actual chamber and brass (internal) dimension specifications are NOT identical. However, it is equally true that the differences have become sort of an urban-legend, old-wives-tale, big-foot sort of thing. Lots of noise, little to nothing really there.

 

[James K]

As I said above, the 5.56 was chosen because it was the only available cartridge that could allow reasonably controllable full auto fire. Adopting the AK-47 and the 7.62x39 and paying royalties to Russia was NOT acceptable for obvious reasons.

Jim

 

[xandi]

It takes less materel to create one 5.56 round vs. a 308 round or 7.63x39 round

 

[rickyrick]

They sting real bad too.

 

[Metal god]

To answer my question in post #61

The thing I'm having a hard time believing is nobody from any test facility has put a factory NATO round in a test system that measures CUP . Or a 223 in a system that measures PSI . You would think those test would tell us once and for all if a factory NATO round produces more CUP then a 223 or vise versa .

I found this posted in this thread http://thefiringline.com/forums/showthread.php?t=553455&highlight=piezo

Finally, just to show how loopy the pressure measuring is, take a look at the table below. Again, from Ken Green, these are all for the same reference ammunition, identical loads fired in the different measuring instrumentation. These all had original SAAMI MAPs of 52,000 CUP (the reason I selected them). Note how much more inconsistent the ratio of SAAMI CUP to SAAMI psi is, than is the ratio of CIP CUP to psi. It is very consistent. I believe this to be due to the greater similarity of the two CIP test setups. 223 is the odd man out under SAAMI. None of SAAMI's other 52,000 CUP round measure so low on the conformal transducer. I don't know why. The transducer is much more consistent when the same reference load lot is fired at several labs, but consistency and absolute accuracy are not the same thing. Clearly relative rather than absolute pressures are the order of the day here.

Code:
.
Cartridge------------ SAAMI--------------------CIP
____________CUP______psi______CUP______psi
223 Rem____52,000-----55,000......53,664-----62,366
243 Win_____52,000-----60,000......52,214-----60,191
270 Win_____52,000-----65,000......53,664-----62,366
308 Win_____52,000-----62,000......52,214-----60,191
6mm Rem___52,000-----65,000......53,664-----62,366
7mm-08____52,000-----61,000......51,996-----60,191

REMEMBER The above numbers are all for the same reference ammunition, identical loads fired in the different measuring instrumentation. These all had original SAAMI MAPs of 52,000 CUP .

So is that the end of the can't shoot 5.56 in 223 chamber debate ?

 

[Deja vu]

It wasn't anointed by the people who had to use it and rely on it.

For sure. My father hates ARs. Lost a buddy because there where 2 failed ARs at the same time in his squad.

The more modern ARs (M16s) are much more reliable that there Vietnam counter parts but still my father hates them. I cant say I blame him. For him its personal.