Almost all of the .275 RIGBY barrelled action rifles left Oberndorf as standard in the white 7x57 Mauser, the majority on intermediate length systems.
All those that have passed through my hands bore the Mauser factory serial number as well as the normal Oberndorf proof stamps for the 7x57 round.
It is certain that RIGBY had a commercial interest in baptising the initial cartridge in .275 Rigby in order to escape the anti-Germanic feeling of the time.
Note however that the twist rate remained the standard 1/8.66" designed to stabilise the 173 grain bullet.
There were also at the time several lighter loads, even military, such as the 139 grain for Brazil, the 140 grain for the Chilean Mauser 1912, the 142 grain for Uruguay or the 155 grain for Mexico.
So nothing new under the sun except for a nice commercial success that still lasts today.
The fact remains that the 7x57 Mauser is a fabulous cartridge, very balanced and superbly efficient.

DORLEAC
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