The case for a 40 mm close-in weapon system

Could 40 mm guns succeed in a close-in weapon system?

Yes: greater range, a heavier projectile, and explosive fragmentation effects support the case for 40 mm, near the suggested practical upper end for this role.

A 40 mm close-in weapon system is considered practical, with that calibre near the suggested upper end of the role. Smaller guns generally have less range and projectile effect. An explosive fragmentation shell can act when a target enters its effective cone, reducing dependence on one projectile making a direct hit. That effect can be useful against larger targets and concentrations of smaller ones. The Italian Dardo system already provides an example of this approach to close defence.