Found some old pics of another project.

Seems I had some "used" .30-0 brass from another project. Looks like .30 GNR gone bad. But not much waste around me. I goofed around and found I could make full cylinder length .41 Remington Magnum "shot loads". I probably used some .40 cal. gas check or something close for a top wad. Now days I fashion thin card wads and top off with hot glue. Works much better.

I don't remember the shot size, distance was only 15-20', but it worked. Velocity on he pellets runs upwards to around 1500 fps so it's actually a little faster than most shotgun shells. Whatever it hits makes no distinction from a 10 gauge!

You sure can't buy any .41 Mag. shotshells so it's relatively easy to make some from scrap cases. I even made some for the .45 Colt revolver from .270 Win., I think. The idea borrowed from Lee Jurras Handgun Hunting book where they were making a shotgun from the .45 ACP Colt New Service 1909. They used a smoothbore barrel to much better effect pre-NFA worries. I had to do some tricks to get the headspace right on the "shoulder" but once formed they worked too! I use a tuft of dacron under the shot. Some type of plastic around the shot column is best as the shot "naked" will lead the rifling, if you shoot very many.