I am working on an archaeological site that is associated with Yellowstone National Park, in particular the Mammoth Hot Springs area. I have been trying to identify a cartridge that was uncovered but have not found any information. There is no headstamp and the cartridge is very unique. I would appreciate any assistance in determining the cartridge, manufacturer, and date range for the cartridge. Thanks!
Rim=1.0" x 0.345"
Shoulder Dia.=0.725" x 0.234"