A friend of mine who is disposing of shooter's estates included 9 of the following cases as part of a purchase. He had no idea what they were for, so I got them. No, I don't have any idea where the firearm went. After looking through Donnelly's book on cartridge conversions I believe they are 44-77 cases that have been formed and loaded, but never fired in a chamber. Original case is 348 Winchester. Case was loaded with about 65 grains of black powder.
That is a loaded 45-70 on the left.
The case was reduced in diameter just ahead of the rim. Which is what Donnelly says need to be done to a 348 Winchester case when forming a 44-77 case.
Bill