I have a Lyman reloading manual from 1984 that expresses all pressure values in LUP, and in the section on pressure, describes in detail the crusher method of measurement. The information I have from SAAMI includes a data sheet from 1984, which refers to the crusher method as "the older method of pressure measurement". And the current SAAMI pressure tables date from 1992 (all psi). I'm not entirely clear on when we started using transducers here in the States, but it would appear that there was a transition period. Much like the conversion from the old short chambers to 2 3/4" in the years before WWII, it didn't happen all at once.
