The 17 cm Mittlerer Minenwerfer (17 cm mMW) was developed by Rheinmetall and entered German service in 1913.
It was a muzzle-loading, rifled mortar weighing 1,065 lbs (483 kg) that had a standard hydro-spring recoil system designed for destroying bunkers and field fortifications otherwise immune to normal artillery. It fired 110 lb (50 kg) HE shells, which 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. Furthermore, the low velocity allowed for the use of explosives like Ammonium Nitrate-Carbon that were less shock-resistant than TNT, which was in short supply. This caused a large number of premature detonations that made crewing the Minenwerfer riskier than normal artillery pieces.
In action, the 17 cm Mittlerer Minenwerfer was placed in a pit, after its wheels were removed, not less than 1.5 meters deep to protect it and its crew. Despite its extremely short effective range of 300 m (325 yards), this mortar proved to be very effective at destroying enemy bunkers and other strong points. With the nature of static warfare on the western front, the number of mortars grew from 116 in service when the war broke out in 1914 to some 2,361 by the end of the war in 1918.