I wonder about the actual utility of this. There have been previous attempts to make very lightweight and man portable machine-guns (there was a conversion kit for the Springfield '03 as far back as WWI), but weapons like the French Chauchat, Stoner 63 system or the Charter Arms Ultimax LMG never caught on.
Ther Chauchat was a pretty shoddy design anyway, but the small size and light weight of these designs make them hard to control when firing, and the ergonomics are similar to a full sized battle rifle, which is a bit awkward in CQB situations.
If we want to do a one to one comparison, why not take a C-7 and fit one of those 100 round drum magazines instead?