There are two versions of the 7.92x57 service cartridge. The earlier version uses a smaller diameter bullet (.318" - I bore) than the later, 1905, (.323" - S bore). Using the later type of ammunition in the early rifles isn't so much a matter of bullet diameter vs groove diameter, its the larger bullet in the cartridge neck not fitting the chamber and throat correctly. Earlier rifles were routinely altered to increase chamber neck/throat diameters to allow .323" ammuntion to be used. These rifles will be stamped "S" on the breech. North American ammunition is loaded with a compromise diameter bullet, usable in early and late pattern rifles, with a moderate powder charge, North Americans being unable to differentiate between the two versions.
The Europeans are aware of the difference in the two cartridges, and load both. European ammuntion with the later .323" diameter bullet, as loaded by Norma, RWS, S&B, PPY, Igman, etc., is loaded to full performance, on a par with .30-06.
A rifle chambered for the S bore cartridge, in sound condition, can certainly use full power ammuntion. There are the reservations about German rifles made late in the war. Don't know how many, if any, failed as a result of using standard ammuntion. Many Israeli Mausers are '44-'45 dated, were extensively used, and converted to NATO.
Dave, isn't your licence revocaton hearing the day after tomorrow? Shouldn't you be worrying about something other than handloading 8mm ammuntion?
