JP trigger, with NIW Colt factory FA hammer/disconnector and JP springs. http://www.jprifles.com/1.4.8.2_fc.php

I've been using these since the late '90's in all my M16s and AR15's. They are crisp and break clean, like the proverbial glass rod. I adjust mine so that total trigger movement from untouched to fully depressed is 3/32". It's like an on/off switch.

I run a 3.5-pound trigger spring and 4-pound hammer spring. Perfect.