i have always been under the impression that Ashcroft make there own shafts, and Kam, a different company, make there own.
Ashcroft have changed the material in the shafts and now are better than before. i didnt think there original shafts were that good, i heard that hey were breaking BEFORE stock OEM cv's. Dave correct me if im wrong. there new shafts seem better now.
i see the pic of the mog vs rover, of coarse its going to be bigger, but if you are going to the trouble of making them, get them made from as best as materila as possible, like 4340 300m or ams 6418
then the design and heat treating are a large factor as well.
for those looking for top quality series axles HI-TOUGH Engineering in Australia make them.
Serg