Check out a rock river arms AR.

They are made well and most have chrome moly barrels. That matters.

Military versions use chrome lined barrels because they last longer. 5.56 pushes a whole lot of gas down a small diameter bore and bore erosion over time is real. Also, if you are like most and don't periodically clean it, the chrome moly stands up to corrosion better.

Don't listen to people that say chrome lines barrels are less accurate. USMC hits targets at 500m with open sights. If it's accurate enough for the Marines, it's accurate enough for you.