I don't agree with that all.
Pyrodex did not cause the confusion.
Everyone knows how fluffy that some home made black powders can be which are much less dense than Goex.
Even black powder from other manufacturers can have different densities, just like Swiss does.
It's known that sporting powders can have a higher moisture content and not all manufacturing processes and ingredients for black powders are the exact same.
Those differences were well known way before Pyrodex was invented in 1977.
That's why the whole muzzle loading industry only uses volumetric grains unless weight is specified, so that there are established standards.
Cartridge case capacity is measured by using the grain weight of water because water has a standard density which coincidentally is almost the exact same as Goex.
And that's why the conversion chart is helpful.
But notice that it only specifies Goex 3F Black Powder and even Goex Express 2F was different.
Express was their cartridge black powder.
How could there ever be a conversion chart for homemade black powders when people do not usually ever weigh their powder charges in the field?
https://www.curtrich.com/BPConversionSheet.htm
And that's also why long ago they made a device to measure the relative strength of different black powders like the Palmetto Epruvette: --->>>
http://castboolits.gunloads.com/show...ster-in-Action
Notice that the chamber holds an exact volume of powder and not weight, and that's how powder strength was measured long before Pyrodex was invented.