That’s fair, it’ll also mean that the equivalent of ghost guns will be a sight to see given that making your own smokeless powder is very difficult but making your own black powder is just a pain in the ass (the only component that’s easy to restrict can be extracted from human biological waste). And as far as I’m concerned, if you want to make black powder cartridges so much you’re willing to process urea into saltpetre go ahead. You aren’t getting a modern mass shooting like that