Sherman Bell described making some in an article about BP rifle cartridges. He used milk cartons and said they were wax coated. I suspect they are coated with plastic now, rather than wax. I asked him about this in an email and he responded that he wasn't sure. At the time, I wanted to make some for 28 ga. shells to be used in a 28 with longer chambers and forcing cones. He basically made a punch and a sizing die to form them by pushing them through it. I made the cups OK but loading them into the shells was too much of a chore. I gave up trying to make good BP cartridges for the 28 hammer gun.
One of the foreign ammo companies announced a couple years ago that they were making paper shot cups for their shells. I emailed them about buying some but never got the courtesy of a reply.
