Also of Joseph Unger, Graz:

http://www.hermann-historica-archiv.de/a...;db=kat48_S.txt

and another one:

https://www.waffengebraucht.at/node/231510

and here you find a discussion in spanish on an Unger Drilling:

http://www.fullaventura.com/foro/viewtopic.php?f=22&t=121916

Of course Raimey is right, it was made for Unger probably in Ferlach.

Kind Regards,
Wolfgang