Try Wal Mart or any of your "good" local gun shops. They should be able to order a gun for you. .50 cal is the most popular by far, but I also shoot a .54. I would also call Cabelas to see if they just didn't list the .54's, they have a "muzzleloaders catalog", so asl them to send it to you. I know CVA still makes in-lines in that caliber, as well as Thompson Center. Both are serviceable guns in the price range you mentioned