The Troy MRF is the strongest user-installed free-floating rail system in the world. Troy MRFs are available for all M16/M4 weapon systems equipped with the original factory barrel nut. The MRF’s patented mounting system reinforces the barrel nut with a sturdy clamp and anti-rotation alignment lugs. Troy MRF BattleRails provide an uninterrupted rail extension and hand guard aligned perfectly with the host weapon’s flat-top receiver. Troy M16 Free Floating Rails M16 Free Floating Rails for all M16 type rifles and carbines. Only adds 4.5 oz. Requires use of low-profile gas block. Features: - Accepts Quick Detach 360 push-button swing swivel. - Only adds 4.5 oz. to weight of M16. - Black