Colt 6920, LMT SPM16, and Daniel Defense DDM4 are high quality weapons, and all proven in US military use. This is product integrity, not flash & marketing.
M4 configuration is light weight, easy shooting, and very capable of good accuracy with quality ammunition.
Daniel Defense at 731 yards
Add an Aimpoint PRO of Vortex Crossfire in a LaRue mount, based on budget.
The brands I suggested have extremely good resale potential as well, in the event you choose to drop the AR platform or want something more mission specific.


My description of the AR marketplace by price.
"Gucci guns"
Tier 1 Mil-spec.
Tier 2
Tier 3 bottom feeder garbage.