St Chamond Obusier de 400 Mle 15-16
In 1915 the French Ministry of War issued an order for the construction of railway guns for use during the projected Verdun offensive. It was decided to modify a good number of leftover naval guns and convert them into 400mm L/25 caliber howitzers. The barrels had to be shortened and recalibrated, because all the guns chosen were of the 340mm L/42 and L/45 caliber guns. Between 1915 and 1917 St. Chamond company converted the guns that became known as “Obusier de 400 Modèle 1915/1916”. In total 13 naval guns were transformed from decommissioned ships and from a canceled battleship class. In addition, St. Chamond manufactured the railway carriages, limited to a maximum weight of 17 tons per axle. The firing rate of these pieces was one shot every 5 minutes since the reloading tasks were really complicated. The recoil of these pieces was so great that a hole had to be made under the barrel block to prevent it from hitting the rails when firing. In addition, an immobilizing tile had to be installed to avoid as much as possible the movement of the carriage after the shot. This way there was no need to constantly reposition after each shot. Despite their drawbacks, these howitzers were the favorites of French artillerymen in WWI thanks to their firepower. In June 1940 there were still ten of these howitzers, of which eight were captured by the Germans, who designated them as “40cm Haubitze (E) 752 (f)”. One of these howitzers was used in 1943 to test the “Röchling” type experimental piercing shells, fired against an old French fortification. Six were assigned to the 693 and 696 batteries which used them in the Siege of Leningrad. It is more than likely that they were destroyed in the summer of 1944, but nothing is known about it.
St Chamond Mle 15-16 gallery and more info