I have said it before,and I will say it again,"What the US Army needs to do is have someone pick up a phone and call the FN headquarters in Belgium and get a quote of a shipload of FN-FAL's in 7mm Mauser caliber,bayonets,cleaning kits,and repair parts. No money and time wasted on research and development while trying to re-invent the wheel.
The 7mm Mauser round IS the round they say they are looking for. It has a heavier bullet that is a spire point boat tail design to buck the wind and hit hard at long ranges,and it and the cases have been in production for over a century. No research and design teams needed,no expenses involved in tooling up for it,just pick up a phone and order as much as you want.
The FN-FAL design itself is superb in every respect. It even has an adjustable gas cylinder so you can tune it for light or heavy loads,and it has been in production since the at least the late 1950's. There ARE no bugs to be worked out.
AND........,you can start issuing them to the troops as soon as the boat gets here.