It was developed for use by engineer troops after the
Siege of Port Arthur during the
Russo-Japanese War of 1904–05 illustrated the usefulness of this class of weapon in destroying bunkers and fortifications immune to normal artillery. The 25 cm schwerer Minenwerfer was a
muzzle-loading, rifled mortar that had a hydro-spring type recoil system. It fired either a shell or a
mine shell; both containing far more explosive filler than ordinary artillery ammunition 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 the use of explosives like
ammonium nitrate–
carbon that were less shock-resistant than
TNT, which was in short supply. Shells filled with these substitutes nonetheless were the cause of many premature detonations, making the riskier for the gun crew than normal artillery pieces. File:25 cm minegranat.png|To the left, a 25 cm schwerer Minenwerfer
mine shell; to the right, a 24 cm conventional
high-explosive shell. File:25 cm minenwerfer.png|25 cm schwerer Minenwerfer in a trench. The left soldier is showing a 25 cm
mine shell as used in the artillery piece. File:25cmMinenwerferCrewLoading.jpg|Loading a 25 cm schwerer Minenwerfer. == Service ==