FN America 503 Magazine 9mm Luger FN 503 8rd Black Detachable. Specifications for FN America 20100261 503 Magazine 9mm Luger FN 503 8rd Black Detachable: Manufacturer: FN America Gun Make: FN Herstal Caliber: 9mm Luger Magazine Capacity: 8 Round Finish: Black Capacity: 8 Package Contents: FN America 20100261 503 Magazine 9mm Luger FN 503 8rd Black Detachable