So here some more pics.
Basic rifle is signed Miller&Val.Greiss München, 16-65/16-65/9,3x72R, nitro proofed shotgun barrels, the 9,3 barrel is proofed with blackpowder and has deep lead grooves.Proofed 1908 in Zella Mehlis. Mounted is an Zeiss Diatal 4x32.
Second barrel is made by Max Möller Zella Mehlis, 16-70/16-70/6,5x58R (Sauer&Sohn), nitroproofed August 1941 in ZM. Mounted is an Kahles Wien 4x. For this barrel there is also an .22 insert barrel passed in the right shotgun barrel, made by Krieghoff.

Maker is so far not known, see my thread:
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=188218&an=0&page=0#Post188218