I used to use 444 Marlin brass and had a FL sizer for it that came off a gun show table. I think I ended up not FL sizing when they got sticky by only turning it down far enough to let them chamber up again.
That was about 20yrs ago. I recently pulled Grandads IJ .410 out, threw some .444 based 7 1/2 loads in and it popped the can out at 25yd. right off. Full choke & pretty tight. Might try a speader.
Nothing fancy here, TP wadding over powder, the shot and another ball of TP on top, pressed in with a short dowel.
To carry in the field I just stick them up in the loops rather than down and carry spares in a lozenge tin.
I guess if I wanted to be more 'old timey' I would use black powder.