As for the barrel I had got onto one that was a take-off and had been chambered for the a shortened 405 Winchester --the 405 x 2.2. It had been fitted to a Marlin Lever action so needed som work on it. Thr action thread was turned off and a sleeve was machined up and threaded onto it. One downside was that it had two dovetail cuts on the underside and one for the front sight. I had ordered a reamer to lengthen the chamber but had to keep in mind the Lee Enfield magazine length. I decided to cut the chamber to 2.410 and trim 405 Winchester brass to 2.405 and with the cast bullet I intended to use I could load to a COAL of 3 inches. It would also suit a jacketed bullet.
This is the cast bullet ( standard dimensions) but the mould has been ordered to suit the barrel dimensions.