Being modest in size, it fired the heaviest shells of all the artillery pieces designed for the Maginot Line. This weapon was not derived from an existing gun, but was born out of the wish of the CORF for a weapon that could be mounted inside casemates and turrets.
The shells it fired were particularly suited for this task, for they contained 4,57kg or 5,49kg of explosives, depending on the shell model. For comparison, a 75mm shell contained 0,7kg of high explosives.
|Elevation||0 to +40°30|
|Rate of fire||6 rpm|
Despite the fact that the range of the eventually designed an presented weapon was 5,6km, the CORF had plans to replace the weapons with a 105 or 155mm variant, this because of problems with the original barrels: unreliable ballistic characteristics, returning muzzle flames and barrel warp (turret mounted guns).
Most of the 135mm howitzers produced, were mounted inside turrets (34 of the 43). Whenever a howitzer was placed in a combat block (either in a turret or on a casemate mounting) it shared that block with with another weapon, a MG turret for example.
The casemate mounted howitzers (9), or rather the embrasures, can be recognised from the outside by the vertical sliding armour plate. Apart from that, the embrasures look the same as the ones used for the 75mm model 1929 guns. The maximum elevation of the howitzer however, was limited to 40° in order to reduce the size of the embrasure.