Finally figured out what those German Proof marks mean with help from the German Gun Collectors Association. It is chambered for the .333 jeffrey flanged and the barrels/ sights are calibrated for 300 grain full steel jacket bullet.Thats what stm G N 19g mean. The double probably dates to around 1920. The barrels are very good but the exterior especially the underside below the forend shows some pitting. Much of the engraving also needs deepening, is it possible to restore that?
With 300 grain bullets the 333 jeffrey double would be hard to beat. Its mild recoil with adequate punch as compared to the 338 mag makes it a winner always.