I think I tag along with DD and Bunk here ---"dont tease the dragon"
Just cuz it was once in a book dont make it automatically a good idea - if we go back 25 to 45 years some of the information (load dats) in some of those old reloading manuals was downright dangerous - and time has proved that. So the wheel turns, lawyers climb aboard the bandwagon, and now we maybe too far in tother direction - who knows ? (till its too late - that is after the kaboom)
Nuther thing with black powder is what is 3F ? what is 4f ? .... there still is a lot of confusion about granulation and what actually is in there - what size grains make up the grade on the can ?
Black powder also not allasame - when I started out we could get Curtiss and Harveys and Goex -- the C&H was about 30% LESS pressure (and lose some velocity) for a given load than Goex (so Goex was HOT - velocity and pressure) these days we see similar differences in Wano versus Swiss - so 4F Wano in a pistol is gonna be like 3F or 2an half F Swiss ---- they different!!!!
Some fellers are under the spell of the myth that says we cant generate enough pressure with blackpowder to cause any harm in a gun ---baloney !! (I would say Bull$h#T but the word police proly delete it)
The blackpowder dragon is a sleepy old dude but if we tease him enough - he wake up and when he does he breathe fire and smoke that can cause awesome results.