You can purchase these as a complete kit or as individual pieces from retailers such as:
: You will need a hammer spring, trigger spring, and disconnector spring. FAPv1.zip
: If you need the safety selector and detents as well, look for kits from Black Rifle Depot . Fire Control Group - smf tactical, inc. You can purchase these as a complete kit
A full Fire Control Group includes the following mechanical parts, which are not 3D-printed due to the high stress of operation: FAPv1.zip