here is a german who made new stocks for the M 1908 and the GK https://schaftwerk.de/#schaefte

the MS 1908 having the same action size like the 1903 , 1905 and 1910, only the diameter of the barrel may vary.
because its only a stock shipment should be absolute no problem.

imho, fireforming anealed 30 06 brass is the way to go.