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Mortier de 270 mm de siège Mle 1885 (et 1885-1891) de Bange


Heavy artillery

Contributor :
Bernard Plumier      http://www.passioncompassion1418.com
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Location :
Musée Royal de l'Armée
Coordinates : Lat : 50.84360 / Long : 4.39380
General comments on this surviving gun :

Identical items in the same location : 1
Items covered by this file : 1

Front view. The cylindric brake linking the carriage to the wedge is well shown. The front wheels train was only needed for the transportation.

Rear view with the rear wheels train. Markings not read, but a plate on the carriage shows 'Fonderie de canons de Bourges - 1907 - nr 64'.

Zoom on the de Bange breech with platic obturator

Historic and technical information
Denomination :     270 Mle 1885 de Bange Origin :       ( Arsenaux de l'Etat)          

Historic context :

One of the last creations of the famous artillery system whose first born had been adopted in 1877 (90 mm de Bange fieldgun), the 'mortier de 270 mm de siège Mle 1885 de Bange' was also the one with the biggest caliber. Equipped with the typical de Bange breech with plastic sealing and a siege carriage with wooden platform and recoil limitation by the means of eccentric wheels identical to the 220 mm Mle 1880 predecessor , it was improved in 1891 with the an important modernization that will be applied to the 220 mm version only in 1901.

In that improved version 'mortier de 270 mm de siège Mle 1885-1891 de Bange', the barrel was mounted on a rollers carriage that could move backwards on a wedge in order to absorb the recoil. An hydraulic brake was completing the elastic link between the wedge and the carriage. The whole system was mounted on a heavy metallic platform that had to be buried in the ground with the surface just below the earth surface.

In August 1914, 32 such 270 mm mortars Mle 1885 de Bange were available in the Siege units together with the 220 mm mortars of the same system. These reduced mobility units were supposed to participate to the assault of the German fortresses, and were therefore not used during the first months of the war, because of the way the war events had followed...

The obvious lack of heavy artillery in the field units soon facing the position war brought the French headquarter to extract these materials from their units and send them to the heavy field artillery units. The 270 mm mortars only arrived on the front from May 1915, becoming the biggest available caliber for the army.

This weapon designed as a siege mortar had a reduced mobility : it was towed in 4 separate loads when on the roads (horses or automobile traction) or on 3 separate loads on narrow gauge 60 cm railways, its setup in position on the platform being also a vcomplex operation needing up to 15 men and 2 officers for a 8 hours long manoeuvre. They participated to the operations until the end of WW1, but stayed in the depots in May 1940 at the start of the WW2.

A coastal version was developped on the basis of the same barrel mounted on a 'G' carriage allowing a horizontal aiming range of 300 degrees, with the 'Mortier de 270 mm Mle 1889'. Some of these coastal mortars were used by Germany during WW2.

Technical data :

  • Complete description : 270 mm siege mortar, M 1885 (and 1885 modified 1891) de Bange
  • Design year : 1885 - 1891
  • Calibre : 270.00 mm
  • Weight in firing position : 16500 kg (Mle 1885-1891)
  • Weight for transportation : 25 t (4 distinct loads when transported on road, 3 distinct loads when on 60 cm narrow gauge railway) (Mle 1885-1891)
  • Tube length in calibres : 6.67 (rifled part) - 9.63 calibres total length
  • Grooves : 80 constant angle 12 degrees to the right
  • Projectile weight : 152 kg à 232 kg
  • Initial speed : 155 to 309 m/s depending on the propulsive load
  • Fire rate : 1 shot / 2 minutes (Mle 1885-1891)
  • Range : 7900 m maximum
  • Elevation range : 0 to 70 degrees (Mle 1885-1891)
  • Direction range : 30 degrees total range (Mle 1885-1891)