Bore Scope the whole thing, then slug the barrel feel for the tight spots, setup in lathe reach in with your long stylist indicator (Interapid test indicator) and see how straight the bore is approximately where the throat will be for your chamber. You will most likely remove (saw) an inch from the crown end of the barrel leave your self some room when you cut the end off (not the whole inch). Ya Should be able to get a 26" barrel from it if everything checks out. HAVE FUNN