The 40-calibreMle 1927 was derived from the German World War I15 cm L/45 UToF gun as mounted on the large torpedo boat SMS S113 received by France as war reparations. It copied the German gun's semi-automatic action and its horizontal sliding-block breech. It had an autofretted, monobloc barrel. It used 8.967 kilograms (19.77 lb) of powder to push a 40.6-kilogram (90 lb) shell to a muzzle velocity of 700 metres per second (2,300 ft/s).[1]
Mounting
The Mle 1927 was used in single centre-pivot mountings that weighed approximately 13 tonnes (13 long tons; 14 short tons) that were fitted with a 3-millimetre (0.12 in) thick gun shield. The mount could depress -10° and elevate to +28° which gave it a maximum range of 16,600 metres (18,200 yd).[1] The gun had a firing cycle of 4 or 5 seconds with its automatic spring rammer, but the dredger hoists transporting the shells and cartridge cases slowed the rate of fire down to 8-10 rounds per minute.[2]