Some confusion here--no surprise at all!--concerning CIP proof. The CIP "change" in proof pressures in the early 90's was, in fact, only a change in the way pressure is measured, not the pressure itself. 850 bar standard/1200 bar superior or magnum continued to be stamped on British guns until 2006, at which point the bar figures were dropped entirely and replaced by STD under one crown for standard, SUP under 2 crowns for superior. What happened in the early 90's is that the CIP countries, which had been using the old crusher system of measuring pressure, switched to the modern electronic transducer system. Transducers--which SAAMI had been using for quite some time before CIP countries converted--give different pressure readings than crushers for the same shells. The old crusher readings, in SAAMI terminology, are expressed as LUP (lead units of pressure), which you'll see in some reloading manuals. Transducer readings are psi.
So CIP didn't really increase proof or service pressure standards. All they did was express it in numbers derived from transducers rather than crushers. And the transducer numbers are higher (just as psi values are higher than LUP), which makes it look as if pressures were increased. To further add to the confusion, the Spanish proofhouse started marking their guns with the new transducer numbers, while the British proofhouses continued to use the old crusher numbers for their proofmarks--even though both countries converted to the transducer system in the early 90's.
No wonder there's confusion on this subject!
