Historic context :

As early as the first battles of 1914, the Germans demonstrated the importance of heavy long-range guns, which the French Army practically lacked. The unlikelihood of an attack from the sea led some French soldiers to study the use of coastal defence tubes on land missions, pending the development and construction of modern guns expected from 1916 onwards.

Thus, following the work of Colonel Leduc (commander of the 10th RAP), from June 1915, a dozen or so '240 Mle 1884 guns on 'échantignolles' carriage' appeared on the front, manufactured from the tube of the corresponding coastal gun of the Bange system, and a rudimentary wooden carriage similar to those installed on the guns of 19th-century wooden ships and absorbing recoil by friction. The whole system was placed on a wooden platform and fitted with a hydraulic recoil brake, which limited the recoil to 4 metres before bringing the gun back into position using a system of hoists.

However, at the same time as developing his fortune, Colonel Rimailho worked with the Forges et Aciéries de la Marine et d'Homécourt company in Saint Chamond to develop a more modern carriage designed for automobile traction, which resulted in the '240 mm Mle 1884 gun on the Saint Chamond Mle 1916 tractor carriage', 60 of which were ordered between February 1916 and July 1916 and delivered between October 1916 and October 1917.

For transport, these pieces were split into two loads, a tube car and a carriage with the platform. Each of the loads required two tractor lorries hitched in series, each consuming up to 250 litres of petrol per 100 km! Whenever possible, it was preferable to move the loads by 60 cm railway, for which the design had been cleverly conceived from the outset.

This equipment was used for the first time in April 1917 on the Chemin des Dames offensive, and gave full satisfaction during the conflict, mainly used in counter-battery missions. A slightly longer 1917 version of the tube was developed and placed on the same chassis, but was not delivered before the end of the conflict. Some pieces remained in service until 1940, by which time the mobility of the 12 pieces of equipment still available had become completely mediocre compared with more modern equipment.

Technical data :

• Complete description : 240 mm gun, M 1884 on Saint Chamond tractable carriage M 1916
• Design year : 1916
• Calibre : 240.00 mm
• Weight in firing position : 25000 kg (échantignolles carriage) / 31000 kg (M 1916c carriage)
• Weight for transportation : M 1916 carriage : 20500 kg for the tube wagon, 23 000 kg for the carriage wagon
• Tube length in calibres : 26.00 / 20.71 calibres (rifled part) - 26 calibres total length
• Grooves : 72 Progressive angle 1.3 to 7 degrees to the right
• Projectile weight : 161 kg (échantignolles) / 140 kg et 161 kg (M 1916)
• Initial speed : 575 / 800 ms (échantignolles) - 525 / 575 / 614 m/s (Mle 1916) depending on the shell and the propulsive load
• Fire rate : 1 shot / 6 minutes (échantignolles) - 1 shot / 3 minutes (Mle 1916)
• Range : 16500 / 22900 m (échantignolles) - 16500 / 14900 / 16800 m (Mle 1916) depending on the shell and the propulsive load
• Elevation range : +36 degrees (échantignolles), -5 / +38 degrees (M 1916)
• Direction range : 0 degrees field (échantignolles), 10 degrees field (M 1916)

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