The return of 40 mm guns for close defence

Does the return of 40 mm armament reflect small-missile defence or anti-piracy and small-boat interception?

Both. These guns can contribute to missile defence while retaining useful flexibility against small craft and other close-range targets.

Returning 40 mm, 57 mm, and 76 mm weapons show navies revisiting the close-defence problem. These guns can engage missiles and smaller surface threats while remaining more flexible than a narrowly specialised close-in system. The change resembles the Second World War progression from numerous 20 mm cannon and pom-poms toward 40 mm Bofors and then larger anti-aircraft guns. As threats become harder to stop, close-in mounts may grow in calibre and apply Phalanx-style control to a 40 mm weapon. An Italian 76 mm shrapnel round offers another example of a larger gun adapted for close defence. Such systems can defend against missiles while remaining useful against boats and other surface targets.