Interesting. Looks like a good set of tools for learning to so jug chokes. The only jug choke I did was on a .44cal. smooth bore barrel. I put in a fairly long taper towards the breech and a shorter one towards the muzzle. That made sense to me. The jug was 2" long. It was only about .006" deep, but worked a dream with 5/8oz. of shot. I managed to break10 straight with it. I used a brake cylinder hone for the job. The end of the jug was 1/2" from the muzzle thus the "end choke" was 1/2" long.