It's not a gun from Ferlach, it's a "Bockbchsflinte" made in Suhl, Germany pre WWII. Gunsmith was August Wolf (AW), barrelmaker was Wilhelm Kelber (W.K), using Krupp steel.
The rifle cal. ist 8 x 57IR (7,7/8,07mm), Nitro proofed with 14,7g (227gr) steel jacked bullet.