CMC’s self-contained, drop-in trigger module replaces the heavy factory trigger found in many commercial AR-15s and delivers a crisp, clean pull with a consistent, pre-set pull weight. Originally designed by competition shooter Chip McCormick to provide all the advantages of a fine, match-grade, single-stage trigger without having to fit and adjust multiple components. A rigid, steel, trigger housing holds all the factory-tuned internal components in proper alignment for easy, fast installation. Generous, precision-ground sear/hammer engagement surfaces provide a remarkably clean, crisp release while preserving reliable function. Each trigger assembly is tweaked at the factory to minimize take-up and over-travel. Threaded sleeves provide ultra-smooth pivot surfaces for the hammer and trigger. Two, slightly oversized center pins replace the standard, trigger/hammer pins to save wear, reduce friction, and prevent trigger wobble; "Chicago"-style screws prevent pin walk. CMC single-stage AR-15 triggers are available with traditional Curved trigger shoe, or skeletonized Flat shoe that provides a different feel some shooters prefer and gives your AR a distinctive look. Two-stage models also available - see separate listing.