The appeal of a six-inch gun included a larger burst, better range, and greater retained energy than a five-inch weapon. That ballistic advantage imposed a handling cost throughout the ammunition train. Six inches was roughly the largest caliber whose rounds could still be shifted manually, and even then the work was difficult. Five-inch, 4.7-inch, and 4.5-inch ammunition reduced that burden, so caliber choice affected sustained handling and crew effort as well as hitting power.
Notable Point · 1:02:50-1:03:35
Why six inches approached the manual-handling limit
Six-inch weapons retained more range and energy than five-inch guns, but their ammunition sat near the upper limit of what crews could move by hand.