There is a link here to GOEX, and on that site, you can find a map of the lower 48 states, with Distributor company names, addresses phone numbers, and some e-mail addresses for every state, or region. Contact the nearest distributor, even if your state is in another district. Call or Email them. Ask them who is a retailer that sells BP in your area. If they don't know anyone, they will arrange to ship the powder to you directly.
These companies are in the business to make money. They can't do that not selling powder. So, give them a chance to sell you the powder you need.
Yes, its a pain to find a source this way, but its a lot easier than you think. Then ask them for the regulations that restrict how dealers can store BP so that you can figure out how to work with a local gun club, or sporting goods store owner, to meet those restrictions and help the store out, so it can order, and sell BP again. Instead of looking at laws and regulations as Solid, inpenetrable walls, accept them as another challenge to overcome. The problem with retailers is they simply threw up their hands at the new regs, and stopped carrying the powder. They didn't think how it would hurt the rest of their business when they ****** off all the ML shooters. All they did was look at the volume of sales for the last year, and if they didn't make enough money to justify meeting the regs, they stopped selling it. Shame on them. That is no way to cultivate a steady customer base. Every sporting goods store in any city or town is not that far away from a rural area. To meet the safety zone requirements, the store has to have a magazine away from occupied dwellings. So, advertise for such a customer, and make a deal with him to let you use his land for the magazine in return for selling him powder at cost. Or make the same arrangement with a local Black Powder rifle club. A large shipment can be delivered to the retailer, and he in turn can store it in the magazine and fill orders for powder with prepaid orders from the club membership, so he is not investing all his money for the sake of the club. The club benefits because when members run short, or new members join, they can send them to a retailer who can sell them a couple of pounds of powder until they place a big order for the membership of the club. Of course, he is going to charge his price on that powder as that is why he invested his money.
With a dealer selling Black Powder, and listening to the members' likes and dislikes about BP rifles, and Shotgun,s he is more likely to cater to traditional BP rifle shooters, than be stocking the new breed of firecrackers, and he is also going to refer people who ask to the club as both a place to shoot, and to learn about traditional BP rifle shooting. No club has too many members; no retailer has too many customers.