A typical AR-15 does not have a good trigger: My Bushmaster’s factory trigger is heavy and not particularly crisp. I finally broke down and bought a single-stage Chip McCormick trigger group for $176. The advantage of this over other match triggers designed for AR-15’s is that it’s a single rugged unit, easy to install, with a 3.5-pound pull that breaks like glass. Drawback compared to its competitors is that it is not in any way adjustable.
CMC AR-15 Super Match Trigger Group