Bofors 57 mm Naval Automatic Gun L/70

The gun is formally known under a variety of names around the globe. Internally at Bofors (now BAE Systems AB) it usually goes under names incorporating the Bofors term 'SAK', an acronym for 'SjöAutomatKanon', meaning "Sea Automatic Cannon" (literal) or "Naval Automatic Gun" (formal). == Design and development ==

The Bofors 40 mm L/60 anti air gun (1.6 inch) was one of the most popular naval anti-aircraft guns during World War II, used long after the war in a variety of roles. However, as jet aircraft became more prevalent in the post-war era, it was clear the gun did not have the rate of fire needed to effectively deal with these threats. Flying at speeds close to , a jet aircraft flew through the effective range of the Bofors 40 mm gun in too short a time for the gun to fire enough rounds to ensure a hit. Bofors' engineers considered two solutions to the problem. One was to greatly increase the firing speed of the 40 while also incorporating any minor changes that would improve its range. This produced the 40 mm L/70, which remains popular to this day. The other was to design a larger weapon with much greater effective range and a larger explosive load that offset a lower firing rate. This eventually resulted in the single-barreled Bofors 57 mm Automatic A.A. Gun L/60 and twin-barreled Bofors 57 mm Naval Automatic Gun L/60 in 1950. == Ammunition ==

Ammunition for the Bofors 57 mm gun is produced by BAE Systems, Sako Limited in Finland, SME Ordnance in Malaysia and Nammo in Norway. In April 2015, BAE Systems unveiled a new round for the Mk 110 in the design stage called the Mk 295 Mod 1 Ordnance for Rapid Kill of Attack Craft (ORKA), made to achieve one shot kills of surface and air threats. Answering a U.S. Navy requirement for increasing the accuracy and efficiency of naval rounds, the ORKA leverages technology BAE Systems developed for larger 127 mm and 155 mm guided rounds, using a 4-canard actuation systems to guide the round. It is fitted with a multi-mode imaging semi-active seeker that can be guided through laser designation or autonomous targeting by downloading image of the target prior to firing; ORKA retains the 3P multiple fuzing modes. In December 2015, the U.S. Navy revealed they were working on developing a guided 57 mm round for its Mk 110 guns on the Littoral Combat Ship and other Navy and Coast Guard ships. Northrop Grumman was awarded a contract to develop a self-guided 57 mm shell for the Mk 110 in October 2023. On 22 August 2017 L3 Mustang Technology (part of L3Harris Technologies) announced the completion of the Critical Design Review (CDR) phase for the U.S. Navy's MK 332 Mod 0 High-Explosive, 4-Bolt Guided (HE-4G) projectile. The round was developed from the Advanced Low-Cost Munitions Ordnance (ALaMO) program. It is intended for use on the LCS and the new fast Frigate, and the US Coast Guard's Legend and Heritage class cutters. == Variants ==

;Bofors 57 mm SAK L/70 Mk1:Baseline version from 1970. 200 rounds per minute rate of fire, water-cooled. :*'57 mm automatpjäs 7101 (57 mm apj 7101') – Swedish navy version with two ammunition hoists. designation for the 57 mm apj 7103A and 7103B. ;Bofors 57 mm SAK L/70 Mk3:Improved version from 1996 based on the Mk2. Ability to use programmable ammunition. :*'57 mm allmålskanon Mk3' – Swedish navy stealth version for the Visby-class corvette. :*'57 mm Mark 110 Mod 0 Naval Gun System' – Slightly modified Mark 3 The Bofors 57 mm programmable 3P ammunition is designated as Mark 295 Mod 0 in US service. == Users ==

Mark 1 users with its Bofors 57 mm L/70 Mk1. • : :* Madhumati class :* Meghna class • : :* :* • : :* :* • : :* (interim gun, to be replaced by OTO Melara 76) :* (modified version of the South Korean Navy's Bae Ku class) :* (retired) • :* (retired 2022) • : :* :* Perdana class :* :* • : :* • : :* Sea Wolf class (Lurssen TNC 45) (retired) • :Swedish designations: :* 57 mm automatpjäs 7101 (57 mm apj 7101) :* 57 mm automatpjäs 7102 (57 mm apj 7102) :Swedish usage: :* (retired) :* (retired) :* (retired) :* (guns replaced with other weapons) • :* Prabbrorapak class (derivative of Singapore's Sea Wolf class, which was based on the Lurssen TNC 45) • : :* (Post HCM/FELEX Refit / 2x MK3 operational prior to Halifax Class Modernization (HCM) refit) • : :* :* (under construction) • : :* Potsdam class • : :* (The last four ship of the class) • : :* (under construction) • : :* :* :* Reformador class :* • :Swedish designations: :* 57 mm allmålspjäs Mk3 :* 57 mm allmålspjäs Mk3B :Swedish usage: :* :* :* • : • • • Type 31 (under construction) • :US designation: :* Mk 110 57mm gun :US usage: :* Legend class :* Heritage class (under construction) :* :* :* (under construction) == See also ==