HaYen,

I believe SAAMI specifies both actually: 6.5x55 SE is 46,000 CUP & 51,000 PSI. CIP rates the 6.5x55 at 55,000 PSI.

http://www.kwk.us/pressures.html

“There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man.”
― Patrick Rothfuss, The Wise Man's Fear