Aircraft Grade 6061-T6 Aluminum; Free-Floating Barrel Design For Increased Accuracy; Two-piece design for USSOCOM allows for the attachment of an M203 grenade launcher when lower rail section is removed; Free-floating barrel design for increased accuracy; Battle-proven, 6-bolt Bolt-Up System securely attaches handguard to the upper receiver; Grade 8 military specification fasteners; Uninterrupted upper rail platform and Mil-Spec 1913 Picatinny rails; Mil-Spec Type III Hard Coat Anodized Finish