Do note that while the width of the gun may have been larger, sheer barrel width is not at all the whole story comparing something with ludicrous windage from firing simple smooth rocks to a far more modern shell.
BOMBAAAARD!!!... A siege cannon used by the Ottoman Empire during the Siege of Constantinople in 1453. Its diameter is 1054 mm, 100% exceeds the 46 cm guns on the battleship Yamato as the largest cannon in the history.