Call the distributors, and talk to them. They will normally ship any quantity of Black powder directly to you, as long as you pay that Homeland Security charge. It pays for you to buy in at least 5 lb. lots, and, if you can find a shooting buddy or two to place their orders with you, you can reduce the cost of shipping for each lb. of powder even further. Graf and Sons is apparently quite helpful in this regard. If you don't know anyone else who shoots black powder guns in your area, ask at a sporting goods store, and if they don't know, ask to put a sign so someone will call you. It doesn't take many people to make buying black powder this way cheap and hassle free. Websites are great, but talking to people is better. Most of the Distributors have 800 numbers so the call is free. I talked to a distributor in California about locating a dealer in the Lewiston, Idaho area, and he told me to have my friend call him. He would ship the powder to him direct, if there was not a convenient dealer nearby. The distributors are well aware of the problems that were created by the ATF inspectors checking all the retailers, and telling them they had to do this, and that, to continue to handle black powder for sale. The vast majority of dealers dropped black powder because they could not redeem the costs required to comply with the regulations.
If you meet one of those dealers, ask him about the costs. He may be looking at a $300 price tag to buy a commercially made powder safe, and just can't afford it, considering the limited sales he makes. However, an old refrigerator, with a hasp and lock on it will do. Drill holes in the back of it to let air in, and smoke out. Then, he has to keep the powder safe a certain distance from other dwellings. He may need a friend with a farm to place the safe for him. Either he drives out to the farm to pick up powder for his customers, who know to call a day before they come in for it, or the friend delivers the powder to his store on request. For regulations sake, the " friend " becomes an employee- part-time- at $1.00 per year, so that we comply with the letter of the laws. He can store up to 50 lbs. and save money by ordering it a case at a time. If you find that friend for him, and provide him with an old refrigerator, or metal ice chest, and modify it to make it a gunsafe, he can be back in the business of supplying Black Powder to you, and other shooters in the area. If you have a black powder gun club in the area, maybe they can put the safe on its property, and the dealer will help you out sending you new members, while you help him out providing him a safe place to store the powder. Work with him.
