They were used in the "siege warfare" on the Western Front to destroy enemy strongpoints, bunkers and similar "hard" targets which were invulnerable to lighter mortars and field guns.

The US Army handbook described it : "... the use for which it is primarily adapted is in the bombardment of strongly protected targets—dwellings, covered shelters, command posts, entrances to galleries, etc—or in the destruction of sectors of trenches, salients and the like.".

It was a short barreled version which fired a 192 pounds (87 kg) bomb for 1,125 yards (1,029 m), using a propellant charge of 1 lb 9 oz (710 g).

This was followed later by the Mortier de 240 mm LT (long de tranchée) which was a long barreled version with improved firing arrangement and breech-loaded charge which fired a 179 lb (81 kg) bomb 2,265 yards (2,071 m), using a propellant charge of 2 lb 13 oz (1.3 kg).

[4] The US version appears to have been a direct copy of the Mortier de 240 mm LT, i.e. with longer barrel and propellant charge loaded into the breech via a brass cartridge case, was also produced late in the war but it is doubtful whether any were actually used in combat.

The mortar was fired by pulling a lanyard, which activated a primer located in the base of the cartridge case, igniting the propellant charge inside.

The 240mm battery consisted of 4 sections with 2 mortars each, and a combined staff of 7 officers, 215 men, 62 horses, a baggage wagon, and 4 bicycles.

[10] Some 400 were copied and manufactured by Böhler during World War I based on examples captured from Italy,[11] although the Austrians had problems recreating the original powder mixture and their shells suffered from large dispersions.