About all German explosive type cannon rounds cam in two variants - with and without 'Zerleger' (=literally 'disassembler'), which is the self-destruct mechanism Morfiend described above. So if you come across "3 cm M-Gesch. 108 Ausf.A m. Zerl.", it's a mine shell with self-destruction built in.
So much for German engineering Lusche. Can't be all that good if you can still find them around
