I used one of the snail-shaped cappers by Ted Csh for many years. It worked well on my double shotgun, Pennsylvania style rifle & Colt reproduction revolvers. I accumulated a number of plastic tubes which 3/4" endmills came in while still employed as a machinist. These had a tight-fitting slip-on Redcap on each end. I would put powder & over powder wads in one & shot with over powder wad in another.
This worked good in the field hunting. In a situation where shots might come fast &numerous, as in a hot dove field I carried as many as practical & then in a lull reloaded them from shot & powder flasks. Early on in my muzzle loading, I was advised to NEVER load the powder charge directly from a flask.
