Stan;
Some years ago I read a very interesting theory on those Swamped ML rifle barrels. As I recall it was in a publication by the National ML Rifle Association, don't recall its exact name.
Anyway the author explained the flats were put on by grinding. They were placed in a fixture which was tipped up at the muzzle end to give the taper & then pushed back & forth across the top of a large grinding wheel. It was thus a fairly long drawn out process as was much of ML rifle building in those days. His contention was that as the carriage moved back & forth grinding took place faster toward the center as more weight was applied there than near the ends where it was supported on one end. His theory was that when the breech end was ground to the desired dimension they simply quit grinding rather than take the time to continue for a perfect taper. thus he claimed the swamping was more or less accidental rather than intentional.
