The Jacob Grey Ultralight Complete Upper Assembly was designed with the next generation AR-15 in mind. This AR-15 complete upper assembly is built around the 7075-T6 billet upper receiver specifically machined and cut in areas where excess material was unnecessary and areas that see excess use and wear, reinforced and strengthened to give a sleek, refined look, without losing the classic lines of the AR-15 platform. It comes standard with the JG designed 13” free float 7-sided M-LOK hand-guard that is also lightweight and leaves plenty of room for customization or the addition of numerous accessories available for the AR-15 platform. The 13” barrel is chambered in 300 Blackout with a 1:8 twist rate. The barrel is machined from 4150 chrome moly steel and black Nitride finished for corrosion resistance and accuracy. Each barrel is individually head-spaced to the Carpenter 158 bolt. Combined with the 8620 steel carrier and black Nitride finish, this complete upper assembly is extremely reliable and smooth shooting.