This tube is made from high quality American 4130 seamless DOM tubing. The inside diameter is smaller than the original receiver, meaning a full auto bolt will not fit inside. The outside diameter is turned down to the same diameter as the original. The front end has been bored out and threaded to accept an original barrel, the threads have also been timed using an original barrel. The interrupted lugs for the end cap have been machined. The high-quality template has critical dimensions for the cocking slot, magazine well, and ejection port. A milling machine is recommended to finish this tube; however, it is possible to finish it with a dremmel tool. MIG or TIG welding is required for assembly. You may need additional USA made parts in order to be R922 compliant. This tube is not a finished receiver; the buyer can make a semiautomatic receiver from it. No FFL required. All ATF rules apply.