The Super Modular (SMR) HK was designed to replace the standard rail on an HK MR556 or HK 416 weapon platform. This rail system utilizes the stock HK barrel nut however incorporates strength, rigidity, and modularity. Constructed of billet 7075-T6 aluminum and type 3 hardcoat anodized to meet military specifications. The SMR HK includes 3 M1913 picatinny accessory rail sections that mount anywhere along the length of the rail at the 3, 6, and 9 o'clock positions. These sections mount directly into steel inserts, creating a rock solid steel on steel connection. Trusted by our Nation's elite, with their input we developed the feature and performance rich HK SMR.