7mm Blank Pinfire Cartridge

Size: 7mm Blank
Headstamp: blank
Manufacturer: UMC - Union Metallic Cartridge Company - Bridgeport, Connecticut, United States
Additional Info: Just like the ball load, the 7mm pinfire blanks by UMC have no headstamp. All I have come across have a blue wad.
picture of Union Metallic Cartridge Company pinfire cartridge
Picture of Union Metallic Cartridge Company headstamp