My experience with NIDs shows that the early guns, like the Flues before them, can be a little off in barrel length. I've got one that Walter has vetted as being in the records as 30-inch and it is actually 30 3/16 inch. That is the most off I've found. Also, it has been my experience that the NIDs from 1926 to 1935 that I've run a bore mic in have been overbored while those from 1936 on have been true to gauge and dead on the even barrel lengths.
Out of all of my Ithaca's only one of them has bbl size true to the description and that is the wifes 4E Flues with 26" bbl's, SST, raised rib, english stock with a checkered butt of all things.......I even have a 2 bbl set 4E which both bbls should theoretically be the same 30" length..... theoretically.... but they arent.
