This was an experimental cartridge from 1893 on the 30-40 Krag case with the belt added for alignment and positioning in clips. It is unsure if a gun was ever manufactured for this. It was granted patent #503,117 on 15 August 1893. This is also discussed on p. 162 of WRACO Vol. 1 by Shuey. The specimen below is a replica that was made by OPM in South Africa for cartridge collectors. Headstamp would have been WRACO 30 USG
30-40 BENNETT XPL