It's a Fortitude tube - had to drill two holes for the forward breech screws. I mounted the breech via the rear end plug and some strategically placed duct tape and that was my "template" - off to the drill press, went nice and slow, turned out perfect. Yes, a 20" M-Rod barrel, and a Fortitude/Maximus stock ($18.43) and a trigger group from Airgun Revisions, which is a Gen 2 M-Rod trigger less the lawyer spring plus a custom trigger guard. Had to file the slot for the trigger guard approximately 3/4", then she dropped right in.These stocks are so cheap right now, thinking of another bottle build sort of like this, but different, as in rifle form, but would need another trigger group from Airgun Revisions, and so it goes.....