I think I only have one 1938 Turk Mauser, but ~ 50 of the 1903 Turk Mausers.

The 1903 were converted from 7.65x53mm to 8x57mm in 1938, and have already had the magazine modified for a longer cartridge.

The 30-06 and 270 are 3.34" and even longer than the 8x57mm.
The 1903 Turks would be a poor choice for a 30-06 conversion.

The 1938 was built for the 8x57mm, and could be lengthened.

I think the 1903 quality is better, made in Orberndorf, but they are more worn than the 1938 Turks.