You are looking at a colt CSR chambered in 5.56. This rifle comes with a colt brand 16" 5.56 1/8 twist barrel. The receiver is stamped colt sporting CSR15 cal 223 colts mfg co LLC Hartford conn USA on the left side and licensed product of NCHC B/1 Texas on the right side. This rifle comes with a NFG Xterra red dot mounted on top.