Object Title

Gun - 25 cm Trench Mortar (schwerer Minenwerfer - Heavy Mine Thrower)

Gun - 25 cm Trench Mortar (schwerer Minenwerfer - Heavy Mine Thrower)



Object Number



Presented 10 June 2004. This mortar, evidently used in action by the Germans, was captured and brought back from France in 1918 by Mrs Shields father, Colonel Arthur W.Brewill of the Sherwood Foresters and had remained in the same location on the farm for 86 years. Mrs Shields remembered playing on and around it as a small girl.

Physical Description

Comprised of a steel rifled L/3 tube with a hydro-spring recoil system attached to either side of the barrel. Trunnions exist on either side of the barrel enabling it to be attached to two steel plates that are rivetted to a large steel base plate. Through a series of hand operated wheels the barrel can be raised from +30 degrees to +85 degrees of elevation and to permit some traverse. On either side of the base plate are two spigots to which are attached two carriage wheels for transportation. These are removed so that the unit may be fired. The oak spokes are ten in number and although the tyres of mild forged steel have survived, due to corrosion they were not attached to the wheel. It was muzzle-loaded, the cotton bag cartridge being inserted first followed by the 97 kg shell. This had a pre-engraved driving band which had to be inserted so that this band engaged with the grooves. A friction tube was inserted into the breech end and the weapon elevated and fired. Either high explosive or gas shell were fired, a muzzle velocity of 152 metres per second achieved and a maximum range of 878 metres obtained. These mortars were used to destroy large areas of enemy trenches (50 kg of explosive in an HE shell) or to clear barbed wire. Hand spikes are provided for lifting the unit.



Serial Number 2563


250 mm

Inscriptions and Marks

197 S 1916
On recuperator
J.S. 197
Recuperator stanchion
JK R108 No.2563 1917.
Breech face
[Rheinmetall company logo] H18 M1916 No2561 SMW Systeme Ehrhardt
On top of recuperator


Places Germany

Bibliographic References

Herbert Jager, German Artillery of World War One, Crowood Press (Marlborough, 2001), pp. 68-82.


The history of this type of mortar dates to 1910 and following the Russo-Japanese war of 1904-5 one of the lessons learned was that the fire of heavy artillery was not sufficient to overwhelm fortifications.The requirement was for closer quarter weapons capable of delivering a heavy explosive charge onto a target from a few hundred metres away. The task of creating such a weapon fell to the Ingenieurkomitee, the Engineer Committee who had a close link with the German manufacturer Rheinmetall. The plan was for three calibres, heavy, medium and light. The 'heavy' was started first and introduced in 1910 as the schwerer Minenwerfer (sMW) or heavy mine launcher. Interestingly, the mortar was rifled. The effect of its 97 kg (215 lb) shell with a 50 kg (110 lb) explosive filling was equal to the larger 28 cm (11 in) and the 30.5 cm (12 in) mortars which weighed more than ten times as much! This mortar had been offered to the Worcestershire and Sherwood Forresters Regiment prior ro April 2004 by the owner.


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