Bofors twin 57 mm

• Is Artillery — yes • Is Uk — no • Name — Bofors 57 mm Naval Automatic Gun L/60 • Type — Naval Gun • Origin — Sweden • Production Date — 1950 • Service — 1952–1990 • Used By — Dutch Navy Swedish Navy French Navy • Caliber — 57 mm • Part Length — 60 calibres 3.420 m • Weight — Traversing mass: 24 tonnes • Cartridge — 57 × 438 mm R (m/50) • Cartridge Weight — 2.6 kg • Velocity — 850 - • Range — 13,000 m (max) 5,000 m (practical) 5,500 m AA ceiling • Rate — 2 × 130 rounds/min • Crew — 8 • Elevation — -9°/+90°, 30°/s • Traverse — -360°, 30°/s • Design Date — 1950 • Manufacturer — Bofors

The Bofors 57 mm Naval Automatic Gun L/60 is at its core a scaled up version of the famous Bofors 40 mm Automatic Gun L/70, but constructed as a twin-gun system sharing the same receiver/mantle with ammunition feeding from the sides into each gun. The guns were water-cooled and fed by large 80-cartridge magazines that allowed several long bursts to be fired without reloading. • Illustration — French "57mm/60 modèle 1951" on display at Port-Louis naval museum. • Illustration — French "57mm/60 modèle 1951" on display at Port-Louis naval museum.

• Illustration — Dutch Bofors 57 mm SAK 60 on the cruiser De Ruyter. The Dutch were the initial users of the Bofors 57 mm Naval Automatic Gun L/60. As part of rebuilding the Dutch Navy post World War II, the Dutch Navy had requested several naval gun systems to be developed by Bofors for their next generation of naval-vessels, one being a twin-barreled 57 mm dual-purpose gun for the planned s De Ruyter and De Zeven Provinciën. This request led to the creation of the Bofors 57 mm Naval Automatic Gun L/60, which entered active service with the Dutch Navy in 1953 mounted on the cruisers De Ruyter and De Zeven Provinciën.

• Illustration — Swedish 57 mm akan m/50 on the destroyer Småland Following the Dutch example, the Swedish navy decided to acquire the new 57 mm system for a new generation of destroyers in 1950. In Swedish service the weapon was fitted to the s Halland and Småland, both of which entered service in 1956. The weapon was initially designated 57 mm automatkanon m/50 (57 mm akan m/50), meaning "57 mm autocannon m/50", but around 1970 the weapon was redesignated to 57 mm torndubbelautomatpjäs m/50 (57 mm tdblapjäs m/50), meaning "57 mm turret double automatic piece m/50" (literal). The gun was in use until the Halland-class destroyers were taken out of service.

• Illustration — Two French s fitted with 57mm/60 mle 51 turrets on the bow. The Bofors 57 mm L/60 naval gun was also purchased by the French Navy and came to serve on a number of naval-vessels under the designation 57mm/60 modèle 1951 (57mm/60 mle 51) from 1952 onward, although primarily post 1956. The French navy version of the system featured a French designed naval mount that maintained the system in mechanical equilibrium, even when firing. The French mounting was some 8 tons lighter than the Dutch/Swedish version. In French service the gun notably armed light escorts as main guns and larger ships as secondary guns. The following French ships were armed with the 57mm/60 mle 51 system: • The battleship (1952 retrofit) • The anti-aircraft cruiser • The anti-aircraft cruiser • s • T 47-class fleet escorts (also known as the Surcouf class) • T 53-class fleet escorts