I believe the Tube sets for the Majestic are the same as those for the full sized Gent/Statesman, while the tubes for the Majestic junior are the same size as the Jr Gent/Jr Statesman vrII. The finished pens themselves are a little longer, attributable to the hardware on the PSI kits being larger than the CSUSA kits. The Majestic Jr I have is 5.593" long compared to the Jr Gent vII at 5.22" (Both with threaded end cap). The Full Size Majestic comes in at 5.917", compared to the 5.81" of the Full Sized Statesman I have. YMMV (but I'd assume not by much).....