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Fort du Barbonnet
Lat : 43.86237 / Long : 7.43433
General comments on this surviving gun :
Identical items in the same location :
Items covered by this file :
Historic context :
In 1876 France adopted its very first armored artillery turrets, result of the studies of the 'Commission des Cuirassements' and the Commandant Mougin. These very large devices (6 m diameter) in hard iron, with the shape of a inverted bowl and non retractable were equipped with two tubes of 'canons de 155 L Mle 1877 de Bange, sur châssis St Chamond Mle 1881. They needed a 26 men crew for their service.'.
Their price was so high that only 25 were built by the companies Chatillon-Commentry and Schneider (le Creusot). Moreover, they were found obsolete as soon as in 1885 with the crisis of the high explosive shells. In 1888 a special commission launched tests that will be remembered by History as the 'Chalon's camp experiments', where 3 types of new turrets were tested both for their firing properties and for their resistance under attack and bombing. The models tested, created in the idea to replace the Mougin turret, were :
The experiments demonstrated that the Bussière retractable turret was resisting better to the bombing than the rotating turrets, but the elevating mechanism, made with a hydraulic piston system, revealed itself too slow (14 seconds cycle time) and fragile. Hence none of the proposed turrets were adopted and efforts temporarily concentrated in modernizing the existing Mougin Turret. The test turrets were repaired and placed in forts. The 'Bussière' one found a place in the surroundings of the Fort de Souville near Verdun after some improvements (reducing the cycle time to 6 seconds), and took an active role in the fierce fights of 1916.
- a retracting turret Fives-Lille type Bussière armed with two guns of 155 L de Bange. This was the very first Frenche retractable turret, designed by the Lieutenant-Colonel Bussière,
- a rotating turret Saint Chamond armed with two guns 155 L de Bange. With a rolled steel head, it has a similar shape as the ones produced by the same company and sold to Belgium for the Forts of the Meuse, but equipped with French guns with a recoil recuperation system,
- a rotating turret Montluçon armed with a 155C Châtillon-Commentry howitzer, the first French turret with a short barrel.
The Mougin turrets remained in service anyhow, and experiments made in 1901 in the Fort de Pagny-la-Blanche-Côte near Toul gave some improvements that allowed the modernization of some of them. In 1914, they still armed numerous forts and some participated to the battle in Lille and in Manonvilliers.
Meanwhile the Captain Galopin, from the Section Technique du Génie used the conclusions of the Chalon experiments to propose a new retractable turret in 1889, equipped with an ingenious elevation mechanism based on counterwights, much more rapid (4.5 seconds cycle time) and reliable. Still armed with the same 155 L de Bange guns, the 'Tourelle à éclipse Galopin Mle 1890 pour deux canons de 155 L' price proved even higher (4 times !) than the Mougin turrets, so that only 5 such devices were built by the Schneider company between 1891 and 1897.
Technical data :
- Complete description : 155mm M 1877 siege and fortress long gun de Bange under turret
- Design year : 1877
- Calibre : 155.00 mm
- Weight in firing position : 11690 kg - 2530 kg (tube only); 5160 kg (turret carriage St Chamond); 4000 kg (structure)
- Weight for transportation :
- Tube length in calibres : 27.00 (total length) - 20.45 calibres grooved part only
- Grooves : 48 to the right, progressive angle (end at 7 degrees) for tube 1877, constant angle 7 degrees for tube 1877/1916
- Projectile weight : 40.8 kg à 43.5 kg selon l'obus
- Initial speed : 458 m/s to 534 m/s at full charge depending on the shell
- Fire rate :
- Range : 7600 m (Mougin turret 1876) - 7500 m (Galopin turret 1890)
- Elevation range : -5 to +20 degrees (Mougin turret 1876) - -2 to +22 degrees (Tourelle Galopin 1890)
- Direction range : 360 degrees range