.223 vs 5.56 NATO

[Re-Pete]

Anyone know if the proof houses differentiate between 5.56 NATO (62350psi) and .223 (55000psi) when proofing a rifle?

I wondered if this difference sparked off the old "Don't use milsurp in your 223" saga.

The proof rounds are apparently calculated to produce 130% of the cartridge design pressure, and QL states 62366psi for 223 Rem, and 55000psi for 223 Rem SAAMI...............the attached proof stamp pic is of my long throated 30" barrel 223, for which I load 80 grain bullets to a Pmax of 52179 psi, giving around 3000 fps.

Re-Pete

[bradders]

No difference as far as I know, I have chambered rifles in both calibers and had no issues

i have a feeling that 5.56 is a CiP spec and all .223 is proofed to CiP spec and they possibly use the same neck and throat gauges

 

The old .233 vs 5.56 debate is usually led by people who don’t know what they are talking about and it goes back to when Ruger started building .223 rifles using an extremely short throat....which they don’t use anymore, but the myth still exists 

I have built plenty of rifles with a true .223 chamber (0.025”) freebore, and never seen a problem, but most rifles have a longer throat these days and everyone spouts “Wylde” while not really knowing what it is, but all mine are .223 Wylde to placate everyone, but if all I had was a .223 SAAMi chambered Rifle, it wouldn’t bother me in the slightest, I’d still shoot 5.56 down it when I felt like it

[Re-Pete]

Does the 223 Wylde kick off with the standard case? Presumably it has increased capacity.........

I use Lapua cases headstamped "223 Match".

Pete

[Andrew]

It is a matter of the methods used for measuring the pressure for SAAMI and CIP.  They use differnt methods and get different numbers. I have shot thousands of round of 5.56 NATO through ".223" chambers.~Andrew