Antique United States Navy Machinist’s Mate Fireman Apprentice 10K Pin MMFA USN Aug 16, 2022 antique Antique United States Navy Machinist’s Mate Fireman Apprentice 10K Pin. The pin has the abbreviated rank / title MMFA USN on the front. Measurements: 7/8″ long by 3/4″ wide Weight: 2...