Rough drawing of a random thought. I won't explain the why
Obviously just a hypothetical but basically you would load it as follows:
- load a 577 snider case loaded with powder and sealed off like a brass shotgun shell (card and liquid glass)
- close the breech.
- load the wad from the muzzle.
- load the ball/shot/slug and any required over shot wads.
As can be seen by the difference in size between the case mouth and bore, this is very much designed as a big smooth bore.
Anyone see why it wouldn't work?