The Darne was a French gas-operated machine-gun produced from 1922 to 1939. It was chambered for the 7.5 mm French Service round which was fed from a 100 or 250-round metal belt system, with a rate of fire of 650 rounds-per-minute. They were used by a number of European countries to equip aircraft during the 1930s. Various models were produced usin... Found on http://www.probertencyclopaedia.com/browse/FMD.HTM