I have a 256 Gibbs Magnum on a 1903 Greek M/S.
A sporter rifle built by Geo. Gibbs.
The Jeffery looks like a sporter built on a Greek Military also.
The chamber in mine will not accept the slightly larger base of the Swede Mauser cartridge.
It is a standard(?) Mauser base dia for the 7x57, 8x57, ect.
I form cases from 8x57 brass with a shortened LEE 6.5Swede FL die to push the shoulder back.
The cases also need the body dia at the shoulder reduced. I induce that with a shove into a 303Brit FL size die.
There doesn't appear to be any alterations to the 1903 rotary magazine or feed guide to make the 256Gibbs Mag work.
Wish mine looked as nice as that Jeffery!
