Canon de 305 modèle 1906/10 à glissement

The Canon de 305 modèle 1906/10 à glissement was a French railway gun that was designed and produced late in World War I and delivered in January of 1919. These guns were held in reserve between the wars then mobilized by France during World War II. Although the majority of combatants had heavy field artillery prior to the outbreak of the First World War, none had adequate numbers of heavy guns in service, nor had they foreseen the growing importance of heavy artillery once the Western Front stagnated and trench warfare set in. Since aircraft of the period were not yet capable of carrying large diameter bombs the burden of delivering heavy firepower fell on the artillery. Two sources of heavy artillery suitable for conversion to field use were surplus coastal defense guns and naval guns. However, a paradox faced artillery designers of the time; while large caliber naval guns were common, large caliber land weapons were not due to their weight, complexity, and lack of mobility. Large caliber field guns often required extensive site preparation because the guns had to be broken down into multiple loads light enough to be towed by a horse team or the few traction engines of the time and then reassembled before use. Building a new gun could address the problem of disassembling, transporting and reassembling a large gun, but it did not necessarily address how to convert existing heavy weapons to make them more mobile. Rail transport proved to be the most practical solution because the problems of heavy weight, lack of mobility and reduced setup time were addressed. The Canon de 305 modèle 1906/10 à glissement started life as six surplus Canon de 305 modèle 1906/10 naval guns which armed Dreadnought battleships of the Danton and Courbet classes. The guns were typical built-up guns of the period which consisted of a rifled liner reinforced by layers of hoops. The 1906 guns used a Manz interrupted screw breech while the 1910 guns used a Welin interrupted screw breech and both fired separate loading bagged charges and projectiles.