If you are using real black powder , always use an animal or plant based lube and if you mix your own use bees wax. Petroleum products used with real black powder forms a hard black gunk in a barrel. When I was a kid I found this out the hard way and then I found out what I was doing wrong. These days I use a lube called Mink Oil I get from Track of the Wolf, but I have also made my own from different ingredients mixed with bees wax. I clean my guns with hot water and dish soap and a brush and patches, rinse with scalding water, and dry the barrel well. Before I store any of my BP guns I swab the barrel with pure Balistol oil. It has done the best in retarding rust during storage for me. There may be a very slight surface rust from time to time, but it never goes any farther.
