cototo24,
If the gun only has 2 barrels, it is not a drilling; it would be either a BBF or BF, depending on how the barrels are arranged. If the rifle barrel is marked 8.2mm it is likely Austrian.The Germans usually marked the barrels with the bore diameter, rather than the groove diameter.The diameter of 8.2mm would fit a .323" bullet;a German gun for this dia.bullet would likely marked 7.9, 7.92(possibly 7.8), of if after 1939 law would be marked with the common name of the Cartridge(ie 8x57 IRS).As Raimey said, good photos will sort this all out.
Mike
