You will need an original parts kit, a barrel (StrlB16), and semi auto tube (StrlSAT) along with this kit in order to have the needed parts. Use of an original barrel may require modification to fit. A milling machine or dremmel tool is required to finish the tube and MIG or TIG welding is required for assembly. A firearm has been built with this kit and classified by the ATF as a firearm and not a machine gun, and uses 9 of 10 allowable imported parts per R922 compliance (with a 16" US made barrel NOT included with this kit).