For the 8x57mm cartridge there was only one bore diameter of 7.9mm or 0.311 inches.
There were two grove diameters, the first adopted in 1888 of 0.1mm for a grove to grove diameter of 8.1mm or .3189", approximately.
The second adopted in July 7, 1896 by a Prussian “All-Highest Decree” N0. 10 345, was 0.15mm, or a grove to grove diameter of 8.2mm or .3228", approximately.
“S ammunition” adopted by order of 4/3/1903, No. 251.03. The “S” bullet had a diameter of 8.22mm (0.3236”). The larger bullet needed the chamber to be modified as the 1888 case was still used. This meant opening up the throat of the chamber.
The chamber was marked with a “S” 3mm high = Rifles suitable altered for S-Munition. 1903-5. An additional 7mm crowned “S” may be found on the right side of the butt.
The preceding information was from “German Military Rifles and Machine Pistols 1871 – 1945”,
By Hans Dieter Gotz. Translated by Dr. Edward Force, CCSU. Includes information on assault rifles and Sten copies.
I seem to remember pictures of the rifle with the old 1888 round nose ammunition. I think it was the from the Alfa Waffenkatalog 1911 reprint.
Contains a photo of UVF with the 1904 rifle
ERRORS CORRECTED !