As per manufacture it will accept ar15 trigger groups "BUT" We do not recommend using aftermarket lighter weight triggers, if you wish to try an aftermarket trigger group we recommend keeping your factory supplied trigger group near by for re-installation as it has more disconnector engagement built into it than a normal mil spec trigger group or after market trigger group.And another "BUT" one glowing review from one gentleman had some doubling Freedom sent him a new firing pin spring no more doubling. Quotes "I've installed a LaRue MBT-2S trigger, an ambi safety lever, and a couple other modifications. The carbine is now absolutely perfect, and fired suppressed or unsuppressed, I love the accuracy and perfect function" Another review "The original trigger is good, but I found it a bit hard to pull. Not sure what it as and whether it would loosen as time went on. I decided on installing a CMC drop in 2# / 2# two stage trigger. I am loving this gun ! It's incredibly fun to shoot"