to assemble the lower you need the following:
-4x 2" 6-32 socket head screws (inserted through the back to strengthen the receiver extension)
-2x 1" 6-32 socket head screw (for reinforcing the pistol grip, and selector)
-1x 1/2" 6-32 socket head screw (for reinforcing the pistol grip, rear)
-1x 5/8" 8-32 socket head screw and 8-32 square nut (the nut is inserted in back, and the screw comes through the bottom to keep the buffer tube from turning)
-1x 1" 1/4x28 screw (for pistol grip)
-2x 2" 1/4 od screw posts (to act as pivot and take down pins)
-1x 1.5" 3-36 socket head screw (to hold the bolt hold open in place)
-1x mil spec mag release
-1x mil spec bolt hold open
-1x mil spec carbine buffer tube
-1x ar15 FCG