This AR-15 drop-in single-stage trigger from CMC Triggers is a superb option for anyone looking to help shrink group sizes and increase accuracy. This non-adjustable preset trigger features a single stage break of approximately 3.5 to 4 lbs. It is designed to work with MIL-SPEC lower AR-15, AR-10 and LR-308 receivers with a .154" trigger and hammer pin hole (small pin). The CMC trigger requires no gunsmithing and can be installed in just a few short minutes.