Designed, manufactured, and field-tested specifically for law enforcement personnel who require an AR-15/M16 dedicated to 9mm ammo using Colt and modified Uzi-type magazines. Integral “leg” hooks over the top of the lower receiver to prevent accidental fall-out during actual combat situations where reliability is paramount. Two-piece, aluminum body features extra tight, mating surfaces to minimize the collection of carbon and brass buildup; scalloped hold-actuator allows unburned powder and other debris to pass through for uninterrupted cycling. Hold actuator is wire EDM-machined from high grade, 01 tool steel and functions with the standard 5.56mm bolt hold-open, which is strong, reliable and more readily available than the 9mm version. (Last round hold-open feature functions with Colt magazines only.) Ejector is of standard, Colt configuration for easy replacement by any department armorer. Funneled magazine well ensures smooth entry for rapid mag changes and limits rotational movement caused by variances in magazine taper. Spring-loaded roller maintains constant tension against the lower receiver well to prevent free play. Steel, feed ramp is heat-treated for extra strength and superior wear-resistance; provides consistent round delivery with most bullet types. Armorer installation recommended. SPECS: Body – 6061-T6 billet aluminum, Mil-Spec black anodized finish. Components – Steel, parkerized finish. Fits all Mil-Spec AR-15/M16 receivers. Armorer installation recommended.