He said, while discussing old-timey methods of determining proper loads, that the 1-1 principle had been successful, but that the principle didn't hold up well above .50 caliber. More importantly, after discussing this idea and some other traditional methods of load development, he very clearly states that you should always adhere to the maker's recommendations for maximum charges and proper granulations. Now that we live in Lawyer Land, I think it would have been wiser to have put that principle in the chapter before anything else. There's always the possibility that someone will mine a nugget of misinformation out of a book and act on it without reading the supporting text.
There have been, and still are available, traditional muzzleloaders that are designed for very heavy charges. Navy Arms made some .58 caliber "Hawkens" that were designed for beefy charges under heavy conicals. Currently, there's a company out in the Northwest that makes large bore underhammers with slow twists designed for roundballs over massive amounts of powder. Their 12-bore uses two caps to ensure ignition. Nice guns, but out of my price range and way more power than I need.
