I have shot my Damascus Guns for 20 years. If you will read some of the DGJ articles that have compared BP with Smokeless, particularly the slower powders such as 7625 and Pb, you will find that BP cartridge pressures were actually higher than the
moderate loads that we shoot.
All of these danger tales were started in the 1950's by cartridge company lawyers putting warnings on their boxes.
Kinda similar to Frogs causing warts , if you believe that one also.