Well my Magnum Disc Rifle has a 26" SS barrel,i have had peps tell me Knight nerver made a disc Rifle with the 26" Barrel.that is pure BS.
Gun's and refrence manual's are like Car Parts book's They are close but not Chisel in Stone.Makes and model's that come out Late in the life of a model/make of a GUN as well as a Car parts ,get thing's change around useing up over stock old parts and useing the newer tool up parts,that are and were nerver documented.I have ran into this problem for over 30+ years of working gun's.But this does not mean just because one does not see it in Refrence Manual or parts book,That it is not nor has it ever been such a thing.It is HIGHLY likely that Knight made a few 24" Barrel Extreme's.No one nor even Knight could tell you are any body else with 100% curtain.That this nerver did nor could it ever happen are did happen for if they did, they would either be lieing are did not know any better