I’ve heard that pistols/revolvers should be loaded with grains equivalent to roundball caliber for optimal performance, like 30 grains for a .30 cal, 45 grains for a .45 cal, etc. Is this true? I’m looking to buy a Philadelphia Derringer in .45, it has a 3” barrel. I’ve never shot a BP pistol with such a short barrel before. Can I load it with 45 grains of powder?