Of all the members in the Minenwerfer family, the light 7.58cm version was the least spectacular but at the same time the most important. It was used everywhere, and was the weapon that supported the German Infantry in all situations, especially during trench fighting, when traditional flat trajectory weapons often were at an disadvantage.
When the war started, the light Minenwerfer existed only in prototype form. (The whole concept of the grenade thrower had long been deemed as obsolete, but had made a return in the Russo-Japanese War.) When the lMW was introduced, it was in the form of the lMW a/A (alter Art, old type), and had a square bedding. As the other types of Minenwerfers, this one too was given to special Engineer units. In the autumn of 1915 each Infantry Division had one Minenwerfer Company, equipped with 2 Heavy, 4 Medium and 6 Light Minenwerfers. Already in the Spring of 1916, the number of Minenwerfer Companies was doubled, while at the same time, special Minenwerfer Batallions was formed. By this time, trials and battle experience had resulted in the construction of a new type of Light Minenwerfer, the lMW n.A. (neuer Art, new type). This had a bedding that was circular at the front and square at the back, and had also a traverse plate, making it possible to traverse the barrel 360°. Like the earlier type, it could be fitted with wheels, and be carried by special poles or simply dragged by men equipped with a special harness. Like the larger 17cm and 25cm minenwerfers there were 2 hydraulic recoil cylinders flanking the barrel and a spring recuperator cylinder above the barrel. The projectile was a normal shell, often from obsolete gun types, with a driving band with lugs which fitted into the rifling. Bagged charges were used as the propellant and the trigger assembly was in the centre of the barrel base.
The new lMW n.A. had its baptism of fire during the Battle of the Somme, and immediately proved its worth as a versatile and useful close support weapon. This led to more and more Minenwerfers being issued to the troops, and it soon became apparent that the Engineers were unable to cope with this numerous weapon, so in the winter of 1916-17, it was organization-wise allocated to the Infantry. The plan was to give each Infantry Batallion 8 lMWs each, but soon it became obvious that because of all the new Machine Guns and other special weapons being issued to the troops, a shortage of manpower loomed, so in May 1917 it was decided to halt the expansion at 4 lMWs per Batallion. The personel used to serve these 4 lMWs were 2 officers and 40 men.
Work on improving the piece still continued, resulting in 1917 in a new variant of the n.A.: this had a tail, very much like a standard artillery piece, only smaller, and a modified carriage, which made it possible to fire it in flat trajectory mode, for example against tanks. It was a good improvement, but it led to a increase in weight: a gun with wheels had a weight of some 258 kilos. (The maximum flat trajectory range was some 1,200 meters, given an elevation of 27 degrees.)
At the time of the big German Spring offensive in 1918, the new guns and a new organization was in place: for purposes of training and administration all the lMWs of the Regiment had been drawn together into a single company, equipped with 12 pieces. (In combat, they were still under the control of the individual Batallions.) During the fluid battles of 1918, the problems of supplying these lMWs with ammo became so great, that it was seldom that the full number of guns could be used effectively. Therefore it was decided to reduce the number of lMWs from 12 to 6.
It was a successful weapon, and at the end of the hostilities, more than 10,000 lMWs were in service. Still, it had one big and obvious drawback, namely the weight, making it a very cumbersome weapon in its class. The future belonged to the British solution, the so called Stokes mortar. The lMW was used by the Belgian Army after WW1 and remained in service until the early 30s. Using mortars in flat trajectory mode was revisited in WW2 when Australian troops fighting in the jungles of New Guinea were issued with a low angle adaptor for the standard 3" mortar so that mortar bombs could be delivered without striking trees in the normal parabolic trajectory.
This drawing (click to enlarge!) was made from measurements and pictures taken in the Koninklijk Belgisch Legermuseum in Brussels, De Lakenhal in Yper, Musee la Grande Guerre in Perrone, Hill 62 Museum near Yper, Wehrtechnisches Museum in Koblenz, Sachsisches Armee Museum in Dresden and the Imperial War Museum in Duxford.
| Calibre | 7.58 cm |
| Weight (without wheels) | 163 kg |
| Weight (with wheels) | 195 kg |
| Max. Range | 1300 m |
| Min. Range | 300 m |
| Shell Weight | 4.5 kg |
There are a large number of surviving lMWs around the world. In the state of Queensland, Australia there are 11 known surviving lMWs - these are documented with some detailed walkarounds on the AMMS Brisbane website
The following surviving lMWs are at the Army Museum at Brussels, West Paterson, NJ., Oxford, Maine and Cookstown, Ontario, courtesy of Philippe Massin, Mike Casale, Stephen Brezinski and Arie Dijkhuis
