Axel has a dissertation on the 8x57IR and this may be a portion of it:
"Apparently the changeover was completed 1926. Jon Speed's book "Original Oberndorf Sporting Rifles", page 274, shows a table of cartridge dimensions agreed upon July 23, 1926 by the German arms and ammo manufacturers association. It shows new//old designations: 8x57IR // M88/8 mit Rand or M88B, 8x57I // M88N, 8x51 // M88/8 kurz or H, 8x57IS // M88/8S.
The German M1888 cartridge was loaded with a .318" 14.7gramme = 227grs (roughly 15gramme)round nose bullet. This was the standard/only hunting load up to WW1. The military S cartridge used a .323" 10g = 154gr pointed bullet that never became popular as a sporting load. In WW1 the German army changed to the sS = heavy pointed bullet for machine gun use, bullet weight 12,7g =196gr. This became the standard weight for both the I and S bores close to WW2. Up until after WW2 the I = .318" bullet was regarded as the sporting type, while the S-bore was the "military" one, used on Sporting rifles mostly for the "Magnum" loads to relieve pressures. Only the 1940 proof law introduced min-max dimensions and the strict differentiating between I and S bores. So take any rifle proofed for a 15gramme bullet to be an I bore. "
http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=300554&page=1Cheers,
Raimey
rse
