Note also that in perusing many "Old" US reloading manuals pressures will be given in PSI which were truly LUP's.
The old British 3 Ton pressure was service pressure taken by the crusher method. It translates to approximately 10,640 PSI, so about 1,000 PSI lower than 3" SAAMI pressures.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra