Historic context :

The first German breech loading 21cm bronze barrel heavy mortars were built by Gruson in 1866 and used during the 1870/1871 war in the siege of Strasbiurg, Paris and Belfort. Several successive versions came as improvements with the '21cm Mörser C/70', '21cm Mörser C/71', and '21cm Mörser C/71/83' (or '21cm Br.Mrs.') , increasing progressively the shel weights from 71 to 83 kg, and the maximum ranges from 4000 to 8200 m.

These mortarsdressing was once again modified in 1899 by Krupp, on the basis of the use of steel instead of bronze for the manufacturing of longer and lighter barrels, giving birth to the '21 cm Mörser' also named '21 Mörser C/99'. Still, this new version was not a modern weapon, with a basic and poor manouvrable carriage, and without any integrated recoil brake or recuperator. Born in 1899, it was therefore really obsoletes some years after only.

This fact did not prevent the German Army to sample out 48 of these old mortars from the arsenals in 1914 ( and several others afterwards) in order to reinforce the numbers of the German heavy artillery already equipped with modern 21 cm M 1910 mortars, more mobile, shooting the same deadly 120 kg projectiles at a longer range (9400 m instead of 8200 m), with an incomparable fire range and precision thanks to a modern recoil recuperating system

This weapon important weight needed ils dismounting into separated loads for transportation : the firing carriage with its small wheels that had to be replaced by a transportation carriage with larger wheels, the tube transportation wagon, and the accessories wagon

Technical data :

• Complete description : 21cm mortar (M 1899)
• Design year : 1899
• Calibre : 211.00 mm
• Weight in firing position : 4820 kg
• Weight for transportation : 6380 kg in three separate loads without the munition wagon
• Tube length in calibres : 10.00 (total tube length) - 7.2 for the grooved part only
• Grooves : 64 progressive angle 5°7' à 11°50'
• Projectile weight : 83 à 120 kg
• Initial speed : 350 to 308 m/s
• Fire rate :
• Range : 8200 to 7200 m
• Elevation range : +6 to +70 degrees
• Direction range : none

• German Artillery of World War One           Herbert Jager                   Crowood   2001  
• Deutsche 21-cm Morser 1911-1945, Waffen-Arsenal #162       Wolfgang Fleischer                   Waffen-Arsenal   1996  
• Les 'Mörser' de calibre 21 cm - Atouts majeurs de l'artillerie allemande en 1914-1918 - Tank Zone Nr 11       Général Guy François                   Histoire et Collection   2010  
• Das Geraet der Schweren Artillerie vor, in und nach der Weltkrieg       Herman Schirmer                   Bernard und Graefe, Berlin   1937