Apparently he rusted his barrel out and blames the powder.
I respectfully disagree with the assesmentabout Pyrodex powders.
I have used Pyrodex in both my rifle and my BP revolver nearly since I bought them in 1995-6 and 1988 respectively. proper(?) cleaning after every shoot and mine never rusted.
The question mark is because when I was new to BP I treated said navy colt just like a modern revolver, cleaned with Hoppe's #9 solvent (not the BP stuff) oiled with whatever gun oil I was using at the time (Rem oil, Hope's oil or CLP) and put away. I have hundreds of rounds down both weapons, and in spite of long term storage neglect both weapons are in fine shape. I will admit the revolver is in less than new condition, but the issues it suffers are owner error and neglect, not the powder used.