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12mm Pinfire Cartridge

Size: 12mm
Headstamp: U
Manufacturer: UMC - Union Metallic Cartridge Company - Bridgeport, Connecticut, United States
Additional Info: In 1873, a few years after the American Civil War, UMC began making pinfire cartridges for nearly 50 years. They made them in 7mm, 9mm and 12mm.
picture of Union Metallic Cartridge Company pinfire cartridge
Picture of Union Metallic Cartridge Company headstamp