The CM is a touch longer than the 47L giving it 3.5gr more capacity. You can run the numbers in QuickLoad to see the potential difference.
BUT, the CM uses a large primer instead of a small primer(like the 47L). So it might not actually survive so well with comparable competitive loads used with the 47L.
BUT, for colder hunting, I would prefer the large primer to lite that capacity. And the CM capacity is more inline with needed for ~139-140gr bullets(only ~123-130gr for the 47L).
They are both excellent mid-range cartridges(by design) that are sparsely stretched to 1kyd for some reason. But that'll fade away to 260s soon -in 26cal..
IMO, the 6x47L is superior to both at 1kyd, matching the 6Dasher(a real, multi-record holding 1kyd cartridge).
I think the 6x47L will be a very successful 6mm in 1kyd competitions.