The FN -15 is built with durability and reliability at the forefront. Starting from the inside out the Upper uses a tried and true carbine length direct impingement arrangement that is meant to give this upper the best ability to run a variety of ammunition. The Upper itself is made with high quality mil-spec aluminum receiver that gives this rifle a wonderful level of strength to weight and rigidity. The traditional 2 Piece polymer handguard is light and adds a good amount of protection when the gun gets hot. And at the heart of this fantastic upper it comes with a Cold Hammer forged barrel for getting the best shooting potential.