Mystery fragmentation item

[Fred]

Does anyone recognise this item, apparently repurposed as a mortar and pestle. Although it is similar in appearance to the German model 1913 kugelgtranate, it is much larger at 11cm diameter. Its probably too heavy to throw far by hand and I'm wondering if it is part of a rifle grenade or something.

 

[kz11gr]

From a WW1 German grenade

 

[Panzerfaust]

Yes, mini mortar Made from German ww1 handgranade

 

[Alpini]

A Kugelhandgranate has a diameter of about 8 cm. Fred wrote that it has a diameter of 11 cm so he is absolutely right that it can't be made from a Kugelhandgranate.