Goran provided this photo of a grenade which is in the collection of a Slovenian military musem.
Apparently this grenade was made during ww2 by the Yugoslavian partizans.
They used confiscated 45 mm Brixia shells from the Italian army as a base for that grenade.
The original italian fuze was removed and replaced with the yugoslavian made percussion fuze.
The tail section has a hole drilled to fit a belt clip.