No correspondence.
One of the disadvantages of this very powerful mortar, was that the range was short, making it necessary to deploy the Minenwerfer in the very frontlines, making it vulnerable to all types of anti-battery fire and other counter-measures. Also, the muzzle velocity was of course quite low, meaning that the speed of the projectiles was equally slow: it was quite possible to see them coming, most of the time tumbling over and over high up in the air, with a very distinctive wobbling sound, making them easy to spot, meaning that the unlucky men at the receiving end had a fair chance to avoid them, if they could move about.
Source:
www.landships.freeservers.com/schw_minenwerf_25cm.htm 