The San Tan Tactical STT15L 6ARC rifle is a superb example of industryleading technologies from companies pushing the envelope with a desire to achieve more. The Hornady 6 ARC cartridge combined with its variety of projectiles currently available allows a significant increase in capability above and beyond what is currently available in the AR15 platform. The capability to weight savings is seen in out STT156ARCLite the slick sided billet matched receiver set without signature lightning pillar cuts. The upper is cut from a single solid 7075T6 Certified Aerospace Aluminum. Propriety special burnished bore that gives a compacted internal surface resulting in a much smoother surface finish. The bore receiver extension face barrel nut threads and barrel extension surfaces are all machined in one operation ensuring that they are perfectly concentric and perpendicular to the barrel assembly.