So why do petroleum based cleaning and lubricating products react adversly with black powder? How about with synthetic powder?
I'm sure Dave can best answer this and if I'm wrong in anything I trust he will correct me. But, it's my understanding that it's simply the chemicals involved. Mixing sulfur-based authentic black powder (like Goex) with a petroleum-based solvent/lube produces a thick, tar-like carbon deposit in the breech and bore of a firearm that makes it nearly impossible to load a second shot unless you swab the barrel quickly between each shot.
As I've found, swabbing with alcohol patches before shot number one does help. However, with my flintlock there is always still some oil I just can't get out of the breech/touch hole area. This causes the dreaded, tarry fowling down deep where my between shot swabbing has no effect. (I actually can see my ramrod not quite making it to my load mark though I'm practically standing on the thing jumping up and down on it. ) I then either have to go in with a breech scraper (which are hard accessories to find anymore for some reason) or my handy-dandy .270 patch holder and thread adapter to try to clear up the breech some.
Obviously, petroleum-based solvents/lubes were not used when muzzle-stuffers like Jeremiah Johnson were roaming the mountains. They would have used rendered animal fat and oil. Interestingly, the main ingredient in "Bore Butter" is vegetable oil. So, one of todays solutions is still to mimmick the old methods. Unfortunately, as has been mentioned, these products leave a lot to be desired in the protection of metal. So then enters "black powder substitutes". Someone sits down and says, "Let's make something that goes boom similar to black powder that isn't so corrosive and doesn't have a lot of trouble with petroleum-based cleaning products." Unfortunately, there still does not exist any substitute that has truly worked out all of the benefits of real black powder without any of the draw-backs that I've found; especially for the flinter!
I'm hoping that a newer breed of cleaning/lubing products will be answer.