the ho-103 achieved a higher rate of fire by using a smaller, lower velocity breda (vickers) cartridge, intermediate in length between the wwii german 13 mm calibre mg 131's 64mm length cartridge, and the long 99mm cartridge of the veteran american m2 browning .50 calibre gun. because of this, the gun was frequently loaded with explosive or incendiary ammunition in an attempt to increase terminal effects on aircraft.