Mike,
I have seen such loading data in RWS and DWM catalogs dating from around the 1930s but certainly not in older catalogs before WWI.
Maybe such information was given on cartridge boxes, but in the case we discuss here there are no known cartridges.
In an old book (by Friedrich von Gagern) have also read complaints about inferior Austrian powders.
Some years ago I inherited a modest collection of hunting cartridges, among them some quite rare Peterlongo cartridges with Roth headstamps. And just these rare things are often falling apart due to corrosion caused by unstable powder. In comparison DWM and RWS specimens are much better.
fuhrmann