The military did not use the SAAMI copper crusher system. They had their own way of doing it. Military copper crusher numbers are not the same as CUP.
The military did use the copper crusher system of taking chamber pressure. If you look at military SCATP standards it simply states that SAAMI standards will be used for taking chamber pressure readings.
And as I stated earlier I have the milspec requirements for commercial contract ammunition made for the military. And the requirement lists 52,000 cup or 55,000 psi for 5.56 ammunition.
The only difference between the .223 and 5.56 are the throats. Now look at the first information at the link below for my Savage .223 throat that is longer than the throats in my AR15 rifles.
HOLLIGER ON .223/5.56 CHAMBERS (Savage .0566 and AR15 .0500 throat length)
http://www.radomski.us/njhp/cart_tech.htm![[Linked Image]](http://i122.photobucket.com/albums/o254/bigedp51/556and223chambers_zps5ee6a6c4.gif)
![[Linked Image]](http://i122.photobucket.com/albums/o254/bigedp51/223_zps6248614d.jpg)
The throat in my Savage is big enough for the M855 cartridge with room left over for the Savage company lawyer. Meaning its the shorter throats that will cause the pressure spike when firing 5.56 ammunition.
And you do not need to test any ammunition yourself, it has already been done, and all you need to do is read.
5.56 vs .223 – What You Know May Be Wrong
http://www.luckygunner.com/labs/5-56-vs-223/
