When I lived up in St. Joseph Missouri, there was a place called Potters, he was retired and loved to shoot trap. He had the best selection of all types of powder I have ever seen, he also carried a large selection of rifle and pistol reloading supplies. He was located right on my way to Pigeon Hill shooting range, so I could pickup anything I needed on the way home. I always remember going in there and seeing Potter at one of the four shotgun reloading presses he had setup to reload for himself.
Down here in Lebanon Missouri, about 25 miles from where I live now, we have a place caller aptly enough "Reloaders". It's right in town but a little difficult to find. As the name says it caters to reloaders. He is a little low on primers right now, but has powder and j-bullets.