I think there's been some discussion here before about shooting .45 Colt from a .410 single barrel shotgun, as works in the Taurus Judge revolver. That would have more punch at close range than .410 slugs or buckshot, but the barrel would have to be reamed or shortened to remove the Full Choke most .410s come with. H&R makes a .45/.410 combo that's made for this, with a rifled barrel for the .45s, and a screw-on choke tube for shotshells. I wouldn't try something like that in an older Rossi, like this one, though.