Check this guy out! this is the badass Core Duty AR-15 from Zev Technologies chambered in 5.56/223. 

ZEV CORE DUTY Rifles are intended for professional end users and serious shooters alike. The Duty rifle features the high quality and aesthetics ZEV rifles are known for. With mil-spec controls and functional upgrades this rifle will deliver excellent performance in the field or on the range. At ZEV we’ve made a commitment to performance driven firearms and the Core Duty rifle is no exception.

Come check these guys out, they are next level. Many others in stock!