It is a somewhat silly idea, since you could get more from a simple shotgun. The reason I'd like one is I hunt in Alaska, where my .45/70 is a must-carry. Right now I've got to lug around two weapons when I'm hunting small game, at least when I'm on a southern exposure slope where the bears could be waking up (we had a warm winter). If I could get some .45/70 shotshells, my Marlin could nail small game and work as my bear gun with the big Buffalo Bore slugs. I have some .45 Colt shotshells I could use in my Ruger, but they're just not powerful enough to hunt big bunnies or ptarmigan. I think they're more for snakes or starling. A .410 would be sufficient, however. There's just got to be a way to turn a big .45/70 cartridge into a de facto .410. Paul B's comments make me think the idea is doomed, though.