MCMR features M-LOK Compatible mounting system Free Float Handguard eliminates loads from barrel, reducing the deflection for more accurate shooting Precision Machined Aerospace 6061-T6 Aluminum Alloy, for high strength and lightweight Proprietary engineered profile offers additional cross sectional strength Steel Barrel Nut (same KMR, MCMR, and QRF series), to resist movement under heat Hard Coat Anodized per Mil-A-8625F, Type III, Class 2