One other reason is that most bullet manufactures publish one chart for multiple bullets. That is a simplification that results in the highest pressure bullet determining the load for all bullets. It also means that the maximum load for different powders may be based on different bullets. It does mean that the chart can be conservative in its own right and makes comparison to other charts difficult as you do not know the exact bullets being compared.Thanks - loads lower than some other bullet suppliers' manuals for same weights. Perhaps because of different bullet characteristics, perhaps for some other reason. Nevertheless, thanks for the effort.