This is a 3d printed AR22 pistol that uses CMMG or similar ar22 bolts and barrels. parts list: -ar15 FCG -ar15 pistol grip -ar15 mag release -ar15 charging handle (with 22 gap filler included) -ar bolt hold open --optional: catch 22 bolt hold open -4x 6-32 x 3/8 set screws -2x 6-32 x 1.25" socket head screws -1x 6-32 x 1" socket head screw -10-32 1.75" socket head screw -10-32 locking bolt --1x 1.5" 3-36 socket head screw (to hold the bolt hold open in place) -1/4" 1.5" screw post -dog tag (optional, for serialization) the 1" screw goes into the inside of the receiver over the pistol grip. the 1.25" screws go into the lower back slots of the receiver. the 3-36 screw holds in the bolt hold open. the 10-32 screw and nut hold the front of the receiver in place. the screw post holds the back of the receiver in place. one of the 6-32 set screws goes in the top of the upper receiver after the barrel has been inserted and the barrel shroud is screwed in place. the other 3 set screws go into the barrel shroud and keep the barrel of from wiggling. the dog tag goes in the dog tag slot and a printed plug goes in behind it, it can be welded in place with a hot knife or soldering iron. if you use an ar15 pistol grip with a rear tab you may need to file a few mm off the top to clear the receiver.