As mentioned above, one problem with the new ammunition was that due to their lightweight nature, the new 20 mm mine shells produced insufficient recoil to operate the 20 mm MG FF cannon. This required a modification of the recoil mechanism so the cannon could fire this new shell, but this in turn made it unsafe to fire the old, conventional rounds. In an effort to avoid the chambering of incorrect ammunition, the modified weapon was redesignated the 20 mm MG FF/M, M for Minengeschoß.
