The Type 1 machine gun was a Japanese aircraft-mounted heavy machine gun widely used during World War II. It was also known as the Ho-103 in general use. The weapon itself was largely based on the American .50-caliber (12.7 mm) M2 Browning heavy machine gun, while the design of its ammunition was initially based on various Italian Breda-SAFAT 12.7 mm rounds. Japanese-designed and produced rounds eventually largely replaced these imported rounds.