And you know what they did to make those, right? They basically took the good old AR-15 and made 3 slightly different versions of it and called them the CAR 814, 815 & 816 all with slight variations like length of barrel and rails etc. How easy was that? lol.
Most of these are basically all derivatives of the M-4 really when you get down to it. They all took the M-4 and made slight modifications and variations and called it SIG or whatever.
But really when you look at the armed forces, each branch has its own MG and they stick to them even the smaller submachine guns the special police forces use are all standardized across each group and their tasks. And the grunts are left with the AKs which is fine by me TBH. I actually like the way they've organized the rifle distribution among the forces. At first glance it might look like it's a mishmash of all types within all branches but it's not. Each group is assigned its particular rifle and they stick to it.