This is a Black Rain Ordnance AR known as the SPEC15 chambered in 223 Remington, model BRO-SPEC-MOE-BW-BTL. 

The Black Rain Ordnance Spec15 series is a line of AR15 rifles and pistols built to meet bid requirements for law enforcement and military personnel and as an affordable option for civilian use. 

Features: 

Black/White Battleworn Finish 

Magpul MOE Furniture 

16 Barrel