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25 cm schwerer Minenwerfer
25cm minenwerfer Waterford Ont 4.jpg
A sMW a/A at the Waterford, Ontario
Type Heavy trench mortar
Place of origin German Empire
Service history
In service 1910–1918
Used by German Empire
Wars World War I
Production history
Designer Rheinmetall
Designed 1907–09
Manufacturer Rheinmetall
Produced 1910–18
Number built approx. 1234
Variants 25 cm sMW n/A
Weight 768 kg (1,693 lb)
Barrel length a/A: 75 cm (2 ft 6 in) L/3
n/A: 1.25 m (4 ft 1 in) L/5

Shell separate-loading, 4 disk charges
Caliber 250 millimetres (9.8 in)
Recoil hydro-spring
Carriage box trail
Elevation +45° to 75°
Traverse 12°
Rate of fire 20 rpm
Muzzle velocity 200 m/s (660 ft/s)
Effective range 540 m (585 yards)
Maximum range 970 m (1,050 yards)
Sights panoramic

The 25 cm schwerer Minenwerfer (German name for "mine launcher"), often abbreviated as 25 cm sMW, was a heavy trench mortar developed for use by engineer troops during the Russo-Japanese War of 1905. This class of weapon was for destroying bunkers and fortifications that were otherwise immune to normal artillery. Heavy mortars were used by engineers to clear obstacles such as bunkers and barbed wire,and other obstacles that longer range artillery could not target.

Design and development

The 25 cm schwerer Minenwerfer was a muzzle-loading, rifled mortar that had a hydro-spring type recoil system. It fired either a 97 kg (210 lb) shell or a 50 kg (110 lb) shell, both contained far more explosive filler than ordinary artillery shells of the same caliber. The low muzzle velocity allowed for thinner shell walls, hence more space for filler for the same weight shell. The low velocity also allowed explosives like ammonium nitrate–carbon that were less shock-resistant than TNT, which was in short supply at the time. Shells filled with TNT caused a large number of premature detonations, making the Minenwerfer riskier for the gun crew than normal artillery pieces.


n/A model in transport mode, with wheels attached, Warsaw

The wheels were removed and the sMW was then placed in a pit or trench at least 1.5 meters deep, protecting the mortar and its crew. Despite the extremely short range, the sMW proved to be very effective as its massive shells that were almost as effective penetrating fortifications as the largest siege guns in the German inventory, including the 42 cm Dicke Bertha (Big Bertha), a howitzer that was more than 50 times heavier than the sMW. The effectiveness of the sMW is indicated by the number in service which increased from 44 when the war broke out, to 1,234 at its end. In 1916 a new version with a longer barrel was put into production. The new mortar was designated 25 cm schwerer Minenwerfer neuer Art (German for "new pattern"), which was abbreviated as 25 cm Smw n/A. The older, short-barrel model was then designated as 25 cm Smw a/A (alter Art)(German for " old pattern." It is unclear what benefit this change had over the older version.

n/A model with long barrel, at the Australian War Memorial, Canberra

Note: The data for this weapon differs between sources and cannot be considered definitive.

Data provided has generally been for an a/A mortar as given at the U.S. Army Field Artillery Museum, Ft. Sill, Oklahoma.

See also


External links

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