FN Non-Reciprocating Charging Handle Conversion Kit (Heavy) for FN SCAR 17S & 20S, Black The Non-Reciprocating Charging Handle (NRCH) assembly upgrade kit gives current FN SCAR Owners even more adaptability and modularity for their rifles with new, non-reciprocating, dual charging handles, enabling any shooting position, grip style or optic choice. The assembly contains a new NRCH bolt carrier, innovative charging handle sled and two ambidextrous, reversible charging handles that lock forward on bolt-close and remain static during fire, providing superior forward assist capabilities. The FN SCAR NRCH assembly upgrade improves the handling characteristics of an inherently more accurate and reliable platform that, in its military configuration, has served Americas most elite fighting forces for more than a decade. FN SCAR NRCH Heavy Kit is only compatible with FN SCAR 17S/20s models. *Upgrading an FN SCAR 16S or 17S requires the assistance of a qualified gunsmith to remove the front plate without damaging the rifle.