De Bange 155 mm cannon

de Bange 155mm Long modèle 1877
155 K 77 cannon at Salpa Line Museum, Miehikkälä, Finland
Type	fortress and siege artillery (initial designation) counter-battery role (WWI)
Place of origin	France
Service history
In service	1877–1944
Used by	France Finland Kingdom of Romania Soviet Union Spanish Republic
Wars	World War I Spanish Civil War Continuation War
Production history
Designer	Charles Ragon de Bange
Designed	1876
No. built	~1,400
Specifications
Weight	5,700 kg (12,600 lb) 6,500 kg (14,300 lb) on cingoli
Barrel length	L27
Shell weight	43.2 kg (100 lb) (1915 FA shell)
Caliber	155 millimetres (6.1 in)
Elevation	-10° to +28°
Rate of fire	1 rpm
Muzzle velocity	561 m/s (1,840 ft/s) with 1915 FA shell
Maximum firing range	12,700 m (13,900 yd) with 1915 FA shell

The de Bange 155 mm long cannon mle. 1877 (or more briefly the 155 L de Bange) was the French artillery piece that debuted the 155 mm caliber in widespread use today. Although obsolete by the beginning of World War I, the 155 L was nonetheless pressed into service and became the main counter-battery piece of the French army in the first two years of the war.

Drawing from the experiences of the Franco-Prussian War of 1870-1871, a French artillery committee met on 2 February 1874 to discuss new models for the French fortress and siege artillery. Among them was a piece in the 14 to 16 cm caliber range. After several meetings, on 16 April 1874 the committee settled on the 15.5 cm caliber. In the subsequent program-letter of the committee, dating from 21 April, the caliber was for the first time expressed as 155 millimeters. (The other two calibers decided by this committee were the 120 mm fortress and siege cannon and the 220 mm mortar.) Three different 155 mm prototypes were tested in Calais in 1876. The winner was Charles de Bange's model, and the French government ordered the first 300 pieces in November 1877.

In common with the other de Bange cannons, the 155 L had a hooped steel construction with gain-twist rifling. In its original (1877) conception, the cannon required a wooden platform from which to fire. Its recoil was absorbed simply by friction with the platform, and the 155 L had to be pushed back into position after every shot. In 1883, the Saint-Chamond hydraulic brake was introduced to better absorb recoil. This brake was a separate piece of equipment that anchored the cannon's carriage to the firing platform and returned it into position after about 110 cm of recoil.

Approximately 1,400 pieces of 155 L were built in the 19th century. Most were placed in France's numerous fortresses of the time (part of the Séré de Rivières system), most notably at Toul, Belfort, and Verdun. In 1882, about 200 pieces of 155 L were retained for offensive operations as siege artillery. In this role, each 155 L gun was drawn by ten horses.

At the turn of the century the de Bange cannons were rendered obsolete by the newer quick-firing guns using the French 75 recoil system, in which only the tube recoiled. Besides the technical obsolesce issue, the French army's doctrine at the time emphasizing mobility—"75 for everything" had become its universal mantra for field artillery. The 155 mm de Bange was therefore retained in forts and in reserve. On 2 August 1914, the French army had 1,392 pieces of 155 L de Bange, either in depots or in fixed positions; not a single one was part of the equipment of a mobile unit. On the eve of World War I, a typical French army corps was equipped with 120 75-mm cannons, while its German counterpart had 108 77-mm, 36 105-mm, and 16 150-mm pieces.