It would be nice if there was a burn rate chart that showed burn rates at different peak pressure limits or whatever causes the wide variations in burn rate for powder used in .45 Auto compared to 9x19 compared to .44 Mag. It just seems that burn rate varies with cartridge pressure and, possibly, volume.
One example would be H335 and BL-C(2). Looking at most burn rate charts, these powder have the same bulk density and the same burn rate (they are generally next to each other with the fast/slow position changing), yet they are NOT the same powder. Sometimes BL-C(2) requires more powder and sometimes less powder to reach the same peak pressure max load compared to H335, but it generally appears slower than H335 based on max charge weight.
I have thought about a mind-numbingly stupid way to create a chart or charts:
For each cartridge, place each powder by charge weight at max load (lower charge weights = faster powder), then attempt to "normalize" the ratings based on cartridge volume and/or max pressure. It may be very unscientific, but I wonder if it wouldn't still be a LOT more useful than the nearly worthless burn rate charts we are currently saddled with.