A MIL-STD-1913 rail, the BCM QRF(Quad Rail Free Float) rail system is built with picatinny rails running the full length of the handguard at 12, 3, 6 and 9 o'clock. Precision machined from high-strength lightweight aerospace 6061-T6 aluminum alloy, the BCM QRF features the same lock up as and steel barrel nut insuring the rail resists movement even under extreme use.Features: Free float quad rail eliminates loads from barrel, reducing the deflection for more accurate shootingPrecision machined aerospace 6061-T6 aluminum alloy, for high strength and lightweightProprietary engineered profile offers additional cross sectional strengthSteel barrel nut (same KMR, MMR and QRF series), to resist movement under heatHard coat anodized per Mil-A-8625F, Type III, Class 2Handguard alone weighs 11.8 ozHandguard mounting hardware 2.3 oz