Vol423,
Your nice rifle was proofed between 1893 and 1911. The 58/50 is the gauge measurement of the rifle barrel's bore (not groove or bullet) diameter. This measurement translates to 10.92mm. The actual groove diameter can be found by "slugging" the bore or when you make a chamber cast, have it extended into the bore. From the marks in the photos, it seems to be black powder proofed, but that does not mean it cannot be used with appropriate "nitro for black" loads.
Mike
Last edited by Der Ami; 08/17/24 12:31 PM.
