Staff Writer (Updated: 5/9/2016):
The German concern of Rheinmetall headed up production of many of the Imperial German Army's heavy weapons during World War 1 (as well as the upcoming World War 2). Design of the 7.58cm class mortar began in 1909 and continued into 1914 to which production was established at the outbreak of war in the summer. The weapon featured a rifled internal barrel design which allowed for strong accuracy at range - as far out as 1,400 yards though made more effective within 328 yards of the target. The wheels of the carriage were typically removed prior to firing its 10lb projectile at elevations of +45 to +78 degrees. Traverse was limited to 7 degrees. A trained and experienced gunnery crew could fire up to twenty rounds per minute as loading was simply through the muzzle end (as in modern mortar weapon systems). Recoil was managed through the integrated hydro-spring system and a typical crew included four to six men. Overall, the 7.58cm weapon weighed in at 200lbs necessitating the multiple crew.
Once in service, the 7.58cm system was initially issued to Imperial German Army engineering crews who effectively utilized the inherent firepower of their weapons to make short work of Belgian and French fortifications and field obstacles. After the stalemate outside of Paris had developed, the weapon was further issued to basic infantry elements for use as a fire support weapon along traditional field mortars. In this way, these heavier German mortar teams could advance alongside allied infantry and machine gun teams, settling into new positions and heavily fortifying them as needed.
Extensive field use ultimately gave rise to a more refined variant in the 7.58cm Minenwerfer n.A. ("neuer Art" signifying its "newer" status) while the original production models took on the designation of 7.58cm Minenwerfer a.A. ("alter Art" to mark their "older" design). Newer marks were differentiated by their longer barrels (16 inches over the original's 9.3 inch type) and use of a circular platform which now allowed for a full 360-degree field of fire without requiring the crew to reposition the entire weapon. The longer barrel allowed for longer ranges to be achieved. A new trail was also developed which allowed the weapon to be used in a horizontal fashion as an ad hoc anti-tank field gun - primarily to combat enemy tanks (then called "landships") which had begun appearing in greater numbers as the war progressed. Both the French and British made heavy use of tanks, forcing the Germans to develop all-new weaponry and tactics to defeat the new foe.
The 7.58cm Minenwerfer N.A. marks were introduced in 1916.