The attached sketch was found in a text from 1922 on "l'Artillerie de Tranche" of the Mortier de 340T. We've recently had some interest in the Italian 400mm mortar (bombard).
The sketch shows the projectile transport and charging of the 340T. It looks as if the French and Italians evolved rather similar designs.
The French 340T was introduced in 1916 but proved to be difficult to transport and was removed from service in 1917. The projectile weighed 195kg with a filling of 93kg of explosive.
This makes the German 25cm mortars look rather feeble.
