76 mm and 40 mm guns for interlocking defence

Beyond a 5-inch main gun, which dual-purpose guns should a ship carry, and why?

The proposal combines at least three 76 mm guns with three 40 mm guns, favouring existing ammunition, range and magazine depth over an all-57 mm arrangement.

The proposed battery combines at least three 76 mm guns and three 40 mm guns for interlocking coverage. An all-57 mm arrangement is expected to encourage acceptance of fewer mounts. The preference for 76 mm also rests on existing ammunition and range, with the spoken comparison putting effective 57 mm fire near 9 km against a 16 km guided-shell figure for 76 mm. The initial rate comparison is roughly 200 rounds per minute for 57 mm against 120 for 76 mm. Magazine endurance matters because rapid fire can consume ammunition in minutes. The 57 mm Mark III example counts 120 ready rounds, 40 in the hoist and 1,000 in the mounting, then estimates less than six minutes at about 220 rounds per minute. Deeper magazines are preferred for cumulative engagements, while the 57 mm remains favourably assessed and its Type 31 fit is welcomed. A new 57 mm mounting or comparable guided ammunition is considered possible, but willingness to fund development is questioned. The proposed fit therefore uses equipment described as already available.