I use the Lee book for data from time to time and I still think it is the worst one as far as "best data". I'm not big on their view of "lead bullet" vs. "jacketed bullet" data. I find that this data almost never gives you a seating depth for the crimp groove to be used and sometimes just seems really far off. I get the feeling that this wild seating depth issue they have is the reason they seem to have their auto disk loads dropping pretty light loads. I could just be making this up, but they do give pretty light loads.