One of the items I failed to mention was that .375 H&H chamber-throat dimensions can vary somewhat, which isn't unusual in older cartridges. This definitely affects maximum powder charges from rifle to rifle, which is one reason some handloaders (including me) pay more attention to the chronograph than specific powder charge.
There's also the basic fact that a controlled-expansion 300-grain .375 bullet at even 2400 fps on Cape buffalo, or water buffalo.Not long ago Berit Aaagard Pace used exactly that sort of handload in Finn's M70 .375 to take both kinds of buffalo, quite neatly. Which once again demonstrates that a good bullet placed correctly is more important than a few extra FPS or foot-pounds.
