The original twist for Mauser barrels in 10.75x68 was 14.17" and the groove size (bullet diameter) was .423”. The 404 Jeffery cartridge was designated 10.75x73 when loaded in Europe so presumably the barrels for this cartridge were the same as used for the smaller Mauser cartridge as is the bullet diameter.

My own original Oberndorf Sporter Mauser opened up to 404 Jeffery from 10.75x68 shoots accurately and stabilises all weights of 10.75 and 404 bullets both of early manufacture and later manufacture.

John Taylor advocated 22” or better still 20” barrels for DG bolt actions as the small loss in velocity that would be experienced in shorter barrels with these heavy bullets still leaves adequate energy. The rifle is handier for use in brush or long grass but depending on the weight of the stock, the overall balance of the rifle could be upset if lopping the barrel too much.

Hope this helps.