Safety, what is more important?

[tdbru]

just as a technical note, part of the difference between load values from 40 years ago published stuff and today, is 40 years ago, all pressures were measured with the copper crusher pressure barrel measurement (Copper Units of Pressure or CUP). Nowadays, most producers are using Piezo strain gauges that are calibrated and measure directly in PSI. squishing the copper slugs was more of an average max chamber pressure as the slugs don't compress instantly. to get a certain amount of compression you need x amount of pressure for y amount of time. inertia in the ram etc. the piezo gauges, on the other hand, react very fast in the nanoseconds, so you can see the instantaneous change of pressure and catch true peak pressures with more precision than before. so some loads that appeared to compress the copper pellet as much as the tarrage table said 50K pounds did in the lab, might have actually had a 75K PSI spike peak pressure, but was so short in duration that the pellet ram and pellet didn't react to that peak in time before the pressure had already dropped. and so now the producers are saying, with the current higher precision measurement capabilities, oops, that old load actually exceeded 65K PSI, albeit very shortly, we need to drop that charge down a bit in our manual.... or something along those lines... obviously not a quote but you get the idea. also might have to do with the particular lot or lots of the canister powder they had on hand compared to 40 years ago too..... that's why it's not a bad thing to accumulate new data manuals through the years.
-tdbru