Steyr? Are you certain that you don't have an Austrian "straight pull" Model 95? Those rebarrled to 8x56R between the wars were stamped with an "S" on the receiver, approx. 12mm tall. The German police made extensive use of those rifles during WWII. How about a pic of the gun? "S", and the Hungarian "H" stamped rifles, should not be used with the original 8x60R ammo. Outfits such as Sportsman's Guide were selling large quantities of original 1938, German stamped ammo about ten years ago. You should be able to find it at gunshows Your 3rd chamber pic seems to show the less pronounced shoulder of the Austrian round, as compared to that of the 8x57.