have heard the 7x57 Mauser was for some years legal after the war and that was the reason MAS made the 7mm barrels for this round. must have been a short period maybe because the bureaucracy made a mistake. Fournier rechamber rifles original made by Mas and build new ones from the stock he got from this maker but all were 7x57 in the beginning so there must have been a reason beside of selling it in the colonys were it was allways a legal hunting cartridge.
have heard at least of one rifle still in the original 7mm mauser chamber so they exist.