Canon de 138 mm Modèle 1927

Canon de 138 mm Modèle 1927
Scale model of the Canon de 138 mm Modèle 1927 gun on display at the Musée national de la Marine
Type	Naval gun
Place of origin	France
Service history
In service	1927—59
Used by	France
Wars	World War II
Specifications
Weight	4,100 kilograms (9,000 lb)
Barrel length	about 5.544 metres (18.19 ft)
Shell	separate-loading, cased charge
Shell weight	40.6 kilograms (90 lb)
Calibre	138.6 millimetres (5.46 in)
Breech	semi-automatic, horizontal sliding block
Elevation	-10° to +28°
Traverse	approximately 300°
Rate of fire	8-10 rpm
Muzzle velocity	700 metres per second (2,300 ft/s)
Maximum firing range	16,600 metres (18,200 yd)

The Canon de 138 mm Modèle 1927 was a medium-calibre gun of the French Navy used during World War II. It was derived from a German World War I design. It was used on the minelaying cruiser Pluton, the destroyers of the Aigle and Vauquelin classes and the Bougainville-class sloops.

The 40-calibre Mle 1927 was derived from the German World War I 15 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).

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). 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.