223 Max Pressure

[CharlieNC]

Sammi max is 55k while CIP is 62k psi. Working up loads for new rem match chamber I have not observed any signs of high pressure when easing up the charge for calculated pressures at 62k based on Quick Load. First why the major difference between the specs, and have others run this high regularly? I would like highest safe velocity node for long range.

 

[ronemus]

IIRC the difference is CUP (crusher) vs. piezo pressure gauge; the specs are equivalent.

 

[johnfred1965]

Google is a great thing. After a few searches, I found that CIP does not distinguish between .223 and 5.56, and uses the 5.56 pressure(62k) in their standard. (also in a 5.56 Chamber) In a 223 chamber with a shorter more accurate leade, I would be careful working up to those pressures. some rifles may take it while others may not. good luck and be careful.

John

 

[CharlieNC]

I understand both are pressures measured in different locations, while cup is simply a copper crush. Hodgdon max charge is based on 55k. Quick Load uses 62k and therefore allows higher charges, and has historically performed well in this regard for numerous applications for me. Interestingly there is only 2k difference in the max spec for the 308.

 

[calgarycanada]

Actually quickload version that I have says max pressure to be 55000 psi. I have gone upto 61000 psi calculated pressure without any pressure signs.
But jut the thought of over pressure scares me, do most of you guys run around 60k or 55k ?

Also just wondering, why is there max pressure difference between say 223 & 308 by as much as 7000 psi ? Case designs??