So, they took all their knowledge and designed a modular weapons system that has both a .223 and .308 version.
We're stuck with the AR platform for the forseeable future I'm afraid.
The 308 should be the weapon of choice, one round they stay down.
Unforrtunately the FN-SCAR costs $2,799 new to civilians the last time I saw one for sale. The military M-16 is less than half that cost to civilians in the AR-15 version.