I have never noticed that it was any worse than BP. With either, clean the gun ASAP after shooting. Don't let it set three days before cleaning or either will eat metal. Both have sulfur in the mix. 777, OTOH, may not be nearly as corrosive since it has no sulfur. That ruins the neat smell, but I'm learning the benefits of 777 lately. I like it a lot for just shooting. I'm not a reenactor nor am I nostalgic for the good old days. I was born in 1952. By the time I was of shooting age, they'd invented smokeless. I got into BP in the early 70s and by the 80s, I could not find BP for sale anywhere, so by necessity, I took up pyrodex. I see little difference, to be frank, except that shipping laws allow stores to actually sell pyrodex and make a profit.