B.S. Pyrodex is not stronger than real bp and you can go for days without cleaning Pyrodex with no rust or other problems.
In the past, mec has posted many comprehensive chronograph readings of many powders being fired through many of his pistols.
Only Swiss powder sometimes exceeds the velocities of Pyrodex P, and certainly not any of the Goex BP powders do. At least not usually, although it could be remotely possible in some revolvers under some circumstances.
That's because Swiss BP is a moist sporting powder that's made using the more potent alder charcoal. And the Swiss don't even produce enough of it for every shooter to be able to load with it even if every shooter wanted to.
The velocity difference between loading equal volumes of Goex vs. Pyrodex P in revolvers can sometimes be 100 fps or more, with Pyrodex P being more potent.
I'm sorry for not clearly explaining the exception for Swiss BP vs. Pyrodex P. Otherwise I'm being accurate unless there are alternate chronograph readings shown to be contrary.
I've reposted so many of mec's chronograph reports in the past, I don't believe that it's necessary to do that all over again.
The integrity of mec's chronograph readings are not usually challenged, although I would be open to viewing any bona fide chronograph results.