"While only the lengths as listed here for the various gauges were available as listed in the catalogs, we must bear in mind that a few very rare special lengths were made. The writer[George Madis]has inter-department correspondence and work orders for the barrel shop that lists special barrels, such a lot of twenty-four barrels in the thirty-two inch for length for the sixteen gauge, made for the Model Twelve in 1937. Another lot of barrels, four in all, were made in the .410 bore, twenty-six inch length, for the Model Twelve. Some thirty-two inch barrels were made for the twenty gauge, and a number of twenty-four inch barrels were made for the twelve gauge."
THE WINCHESTER MODEL TWELVE by George Madis