The Lee book is a compilation of other's load data. Lyman tests their data and give you the equipment data.

In recent years most of the published data has shown reduced powder charges over all. This is due, primarily, to a change in how the pressures are measured. In years past cartridge pressures were measured using small copper or lead cylinders that were measured and compared to pressure tables provided by the cylinder manufacturer. Hence the terms copper units of pressure (CUP) and lead units of pressure (LUP). Now most of those measurements are done using electronic means reading directly in pounds per square inch (PSI). Ballisticians found that some of the charges they were advocating as safe were well over the SAAMI specs for a lot of cartridges, thus the changes. Lee has apparently not caught up with these changes.

Bottom line I'll trust Lyman before I'll trust Lee. Do what you please it's your gun and your hand.