This Andro Corp Industries Bravo 300 Blackout AR-15 Rifle has a 16-inch long Chrome Moly Vanadium barrel with a 1-7 twist rate. It includes a slim, 15-inch M-LOK hand guard, to easily include your favorite add-ons to the rifle. This AR-15's upper with T-marked has been made of 7075 T6 Mil-Spec then dry film lubed to ensure corrosion resistance. Andro Corp Industries 300 Blackout Bravo 16 AR15 is a dependable rifle made with Mil-Spec lower parts, Mil-Spec furniture, and an MPI/HPT M16 Bolt Carrier Group that's full auto rated.