Why five-inch guns dominate rapid naval fire

Which modern naval gun above 100 mm combines the best rate of fire with reliability?

The five-inch class is the preferred answer, with 130 mm systems broadly in the same bracket.

The 4- to 5-inch bracket offers the best balance of rate of fire and reliability above 100 mm, with five-inch weapons as the usual answer. Soviet and Russian 130 mm guns occupy much the same practical category. Larger shells increase handling demands, while smaller weapons give up striking power. The widespread use of this bracket reflects that compromise.