The other issue to remember, when evaluating vintage pressure data, is that you get different psi readings, crusher method vs electronic transducer. Once we went to the transducers, reloading manuals corrected for the difference by referring to psi taken using lead crushers as LUP--or lead units of pressure. So, when you read vintage literature concerning pressure--certainly anything written before WWII--when you see psi, it actually means LUP. Thus, the psi figures I gave, above--for Hunter Arms guns and for the then-current SAAMI standard for short-chambered guns--are actually LUP. Which means, ballpark, you'd have to add about 1,000 to get the current psi equivalent.