Shell weight and the limits of manual loading

Why did later medium-calibre mounts exceed the shell weight judged practical for manual loading?

The benchmark depends on the weapon’s role and circumstances, and real designs must accept compromises when loader technology, weight, and treaty limits rule out an ideal solution.

A maximum effective manual weight is not a universal rule. The role of the ship and gun, along with the operating conditions, matters. A test can identify an efficient handling limit without making every heavier shell unusable in every mounting. Designers may accept a less-than-ideal loading burden when a lighter shell or automatic loader is unavailable. Technology, treaty tonnage, and the intended tactical role can therefore override the laboratory optimum.