hoppdoc:

As a rough rule of thumb only, CUP is usually lower than PSI, but they're not really convertible because the relationship isn't linear. Krieghoff gives 39,885 CUP and 44,962 PSI for their .500/.416. SAAMI lists 35,000 CUP for the .470 and CIP lists 39,160 PSI.

Yes, almost all modern pressure gear is now piezo electric.

Ten tons is BPE pressure so, no, that wouldn't be a good assumption. All of the nitros will be higher.

As this string illustrates, one of the problems with Wright's book is that the pressure data doesn't correlate to chamber pressure (PSI), which is what is used virtually everywhere else today. His use of the term "TPSI" to describe BaseCUP is misleading, as this is easily confused with piezo chamber pressure, and more than a few have made that mistake. "TPSI" was never used in the original data. Pressure was simply expressed as "X tons". At a minimum, with respect to the pressure testing he did at Kynoch, both BaseCUP and PSI were available, as their guns measure both simultaneously. Inclusion of the piezo data would have been of enormous value to handloaders. Also, Kynoch has done extensive testing of Cordite ammo in recent years, so there was no need to limit comparison to BaseCUP only. The suggestion that actual pressures are irrelevant, especially with regard to double rifle cartridges, is patently absurd.
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