Installs on all standard AR15/M16/M4 lower receivers allowing owners to shoot the FN 5.7x28mm cartridge on their existing rifle platform. Assembly comes with a standard carbine buffer for use in all retractable/collapsible/carbine-style stock lower receivers. An available A2-style buffer (not included) is required for standard butt-stock/rifle-stock/A2-type lower receivers. Free-float fluted barrel. Flash hider. Milled 7075 T6 aluminum receiver. Hard-coat anodized finish. Bottom eject (through magazine well). Gen 2 AR57 upper features: ambidextrous magazine release, extended top rail, low-profile folding charging handle, vented tri-rail and upgraded spring and extractor. with two 50rd mags!!!!!!!!!!!
Please feel free to contact me with any questions at 5159919525