Unknown German WW2 20mm device

[pzgr40]

I bought this unknown German ww2 20mm device - of cource completely FFE- and was told it is meant to destroy the barrel of a 20mm gun to avoid capture. Hence the removed driving band so it can be pushed into the barrel to destroy the barrel by exploding it. This seems a bit overdone in difficulty to me as a 20 mm barrel can easily be destroyed by hanging a Stiel- or ei granate beside it.
The device is made from a 20mm MG 152/20 HE shell with a modified practice fuze (with arrow) in which an electric squib has been glued into the nose. I suppose a 13 mm detonator (sprengkapsel A) was placed below the squib, but that is a guess.

My questions:
-Is this really a barrel scuttling device? Or is it some test equipment?
-What is the correct german name for this device?
-Is it rare? I have seen these fuzes with squibs before, but never with the wires attached and a 20mm shell below it

Thanks in advance,
Regards, DJH

 

[LEAFLET]

Hello DJ,

This is wat I found in my documents. I can't remember where it came from.
Maybe you can use it.

LEAFLET