View source for Bofors 40 mm L/60 gun

{{Short description|1930s Swedish anti-aircraft autocannon design}}
{{distinguish|Bofors 40 mm Automatic Gun L/70|Bofors#Guns{{!}}other Bofors guns}}
{{Use dmy dates|date=July 2020}}
{{Infobox weapon
| name               = Bofors 40 mm Automatic Gun L/60
| image              = File:Bofors-40mm-batey-haosef-1.jpg
| image_size         =
| caption            = 
| type               = [[Autocannon]]
| origin             = [[Sweden]]<!-- Country flag removed per [[Wikipedia:Manual of Style#Images]]. -->
<!-- Type selection -->
| is_ranged          = yes
| is_explosive       = yes
| is_artillery       = yes
<!-- Service history -->
| service            = 1934–present
| used_by            = ''See {{section link|Bofors 40 mm L/60 gun|Users|nopage=yes}}''
| wars               = ''See {{section link|Bofors 40 mm L/60 gun|Wars|nopage=yes}}''
<!-- Production history -->
| designer           = [[Bofors|AB Bofors]]
| design_date        = 1930
| manufacturer       = ''See {{section link|Bofors 40 mm L/60 gun|Manufacturers|nopage=yes}}''
| production_date    = 1932–present
| number             = >60,000 (L/60)<ref name="FW">{{cite web |last1=McCollum |first1=Ian |title=Swedish Antiaircraft Artillery: Bofors 40 mm Automatic Gun M1 |url=https://www.youtube.com/watch?v=7dJDn5F1GQk |website=Youtube |publisher=[[Forgotten Weapons]] |language=en |date=24 August 2018 |access-date=19 February 2019 |archive-url=https://web.archive.org/web/20190214184541/https://www.youtube.com/watch?v=7dJDn5F1GQk |archive-date=14 February 2019 |url-status=live }}</ref>
| variants           = ''See'' ''{{section link|Bofors 40 mm L/60 gun|Variants|nopage=yes}}''
<!-- General specifications -->
| spec_label         = 40 mm L/60
| mass               = 
| length             = 
| part_length        = {{convert|2.25|m|ftin|abbr=on}} 
| width              = 
| height             = 
| crew               = 4<ref name="MF">{{cite web |title=Bofors 40 mm (Series) Towed Anti-Aircraft Gun / Air Defense Gun - Sweden |url=https://www.militaryfactory.com/armor/detail.asp?armor_id=786 |website=www.militaryfactory.com |publisher=Military Factory |access-date=19 February 2019 |archive-url=https://web.archive.org/web/20190219130414/https://www.militaryfactory.com/armor/detail.asp?armor_id=786 |archive-date=19 February 2019 |url-status=live }}{{better source needed|date=February 2019}}</ref> (dependent on use)
<!-- Ranged weapon specifications --> 
| cartridge          = 40×311mmR
| cartridge_weight   = {{convert|0.9|kg|lboz|abbr=on}}
| caliber            = {{cvt|40|mm|in|2|abbr=on}}
| barrels            = 
| action             = [[Extractor (firearms)|Automatic extraction]] and integrated [[Cam (mechanism)|cam]]-operated [[recoil]] powered [[autoloader]]
| rate               = {{ubl
  | '''Low elevation angles''':<br/>140 rounds/min
  | '''High elevation angles''':<br/>120 rounds/min}}
| velocity           = {{convert|850|–|880|m/s|abbr=on}}{{efn|L/43: {{convert|700|–|730|m/s|abbr=on}}}}
| range              = 
| max_range          = {{convert|7160|m|yd|abbr=on}}
| feed               = 
| sights             = 
<!-- Artillery specifications -->
| breech             = Vertical [[Rifled breech loader#The sliding block|sliding-wedge]]
| recoil             = 
| carriage           = {{convert|522|kg|lb|abbr=on}}
| elevation          = −5°/+90°, 55°/s
| traverse           = Full 360°, 50°/s
<!-- For all -->
| ref                = {{sfn|40 mm L/60 Model 1936 (NavWeaps)}}
}}

The '''Bofors 40&nbsp;mm Automatic Gun L/60''' (often referred to simply as the '''"Bofors 40&nbsp;mm gun"''', the '''"Bofors gun"''' and the like,{{sfn|40 mm Bofors (saab.com)}}{{sfn|40 mm L/60 Model 1936 (NavWeaps 2011)}} see [[#Name|name]]) is an [[Anti-aircraft warfare|anti-aircraft]] [[autocannon]], designed in the 1930s by the Swedish arms manufacturer AB [[Bofors]]. The gun was designed as an intermediate anti-aircraft gun, filling the gap between fast firing close-range small calibre anti-aircraft guns and slower firing long-range high calibre anti-aircraft guns. For its time, the Bofors 40&nbsp;mm L/60 was perfectly suited for this role and outperformed competing designs in the years leading up to [[World War II]] in both effectiveness and reliability.{{sfn|40 mm Bofors (saab.com)}}{{sfn|Naval Legends (WoWS)}}

It entered the export market around 1932{{sfn|Naval Legends (WoWS)}} and was in service with 18 countries by 1939.<ref>{{Cite web|title=40 Bofors anti-aircraft gun|url=http://basart.artillerie.asso.fr/article.php3?id_article=501|url-status=dead|archive-url=https://web.archive.org/web/20160322041942/http://basart.artillerie.asso.fr/article.php3?id_article=501|archive-date=2016-03-22|access-date=2022-01-25|website=basart.artillerie.asso.fr}}</ref> Throughout World War II it became one of the most popular and widespread medium-weight anti-aircraft guns. It was used by the majority of the western [[Allies of World War II|Allies]] and some [[Axis powers]] such as Nazi Germany and Hungary.

In the post-war era, the Bofors 40&nbsp;mm L/60 design was not suitable for action against jet-powered aircraft, so Bofors developed a new 40&nbsp;mm replacement design with significantly more power—the [[Bofors 40 mm Automatic Gun L/70]], also known under the generic name 'Bofors 40&nbsp;mm gun'—which was adopted by many nations during the Cold War and was selected as NATO-standard in November 1953.<ref>{{Cite web|title=40mm Luftvärnsautomatkanon m/48/ Bofors 40mm AA-gun model 1948|url=http://www.tfd.chalmers.se/~m95perm/vapen/kanon/div/40mm_akan_m48.html|url-status=dead|archive-url=https://web.archive.org/web/20070701070214/http://www.tfd.chalmers.se/~m95perm/vapen/kanon/div/40mm_akan_m48.html|archive-date=2007-07-01|access-date=2022-01-13|website=tfd.chalmers.se }}</ref> The Bofors 40&nbsp;mm L/60 would however continue to see service long after becoming obsolete as an anti-aircraft weapon due to the massive number of surplus guns from WWII, and a small number of Bofors 40&nbsp;mm L/60 guns remain in service today. Some weapons saw action as late as the [[Gulf War]] and [[Yugoslav Wars]].

== Name ==
The Bofors 40&nbsp;mm Automatic Gun L/60 is known under a variety of names around the world. In common historical nomenclatures it is commonly known under the names ''Bofors 40&nbsp;mm gun'', ''40&nbsp;mm Bofors gun'' and ''Bofors gun''.{{sfn|40 mm Bofors (saab.com)}} This mostly stems from [[Western Allied]] usage of the gun during World War II. For example, British anti-air batteries armed with the gun during the war received the nickname "The Bofors Boys".<ref name="Bofors pm 43">{{cite magazine |date=1943 |title=PM nr 3 mars 1943: Bofors – Notiser |url=http://bildarkivet.karlskoga.se/B-pilen/1943-1946%20BOBORS%20PM/BOFORS%20PM%20%C3%85r%201943.PDF |magazine=Bofors PM: Personal-meddelanden till AB Bofors tjänstemän |location=Sweden |publisher=AB Bofors |access-date=2022-03-20 }}</ref> There were other guns by Bofors which also had these nicknames, the most common being the [[Bofors 40 mm Automatic Gun L/70]], leading some to think they are the same gun.

[[Bofors]] itself never marketed the gun or its variants with a clear standardized name or abbreviation.<ref name="Bofors 36 de"/><ref name="Bofors 47 en">{{cite book |date=1947 |title=Bofors |type=Company presentation and marketing product catalogue ([[Bookbinding|bound]]) |language=en |publication-place=[[Karlskoga]], [[Sweden]] |publisher=[[Aktiebolaget Bofors]] }}</ref><ref name="Bofors 58 en">{{cite book |date=1958 |title=Bofors |type=Company presentation and marketing product catalogue ([[Bookbinding|bound]]) |language=en |publication-place=[[Karlskoga]], [[Sweden]] |publisher=[[Aktiebolaget Bofors]] }}</ref> In the vast majority of 1930s marketing material the gun is sold under a variety of descriptive names depending on the configuration, such as: "40 mm Automatic Field Gun L/60" to "40 mm Automatic A.A. Gun L/60 in Field Carriage" or "40 mm Automatic Naval Gun L/60" to "40 mm Automatic A.A. Gun L/60 in Naval Mounting". This theme transfers over to other languages as well: {{langx|sv|40&nbsp;mm fältautomatkanon L/60}}, {{langx|de|40&nbsp;mm feldluftautomatkanone L/60}},<ref name="Bofors 36 de">{{cite book |date=1936 |title=Bofors |type=Company presentation and marketing product catalogue ([[Bookbinding|bound]]) |language=de |publication-place=[[Karlskoga]], [[Sweden]] |publisher=[[Aktiebolaget Bofors]] |pages=38–43 }}</ref> {{langx|es|Cañón automatico de campaña de 40 mm L/60 Bofors}}.<ref name="Bofors 57/60 es">{{cite book |date=1954 |title=Cañón automatico de campaña de 57 mm Bofors |type=Product catalogue and description ([[ring binder]]) |language=es |publisher=[[Aktiebolaget Bofors]] }}</ref> Only the [[caliber]] of 40&nbsp;mm and [[caliber length]] of L/60 are somewhat universal in branding.

Due to this the gun is often specified by the calibre length "L/60".{{sfn|L/60}} Enthusiasts and experts usually call the gun "Bofors 40&nbsp;mm L/60"{{sfn|40 mm L/60 Model 1936 (NavWeaps 2011)}} or simply "Bofors 40/60" and the like.<ref>{{Cite web |title=Naval Historical Society of Australia: Model makers drawing, 40/60 Bofors Mk 5 Twin Mount |url=https://www.navyhistory.org.au/wp-content/uploads/A014006_40_60_Bofors_mk5_twinmount.jpg |url-status=live |archive-url=https://web.archive.org/web/20210331183149im_/https://www.navyhistory.org.au/wp-content/uploads/A014006_40_60_Bofors_mk5_twinmount.jpg |archive-date=2021-03-31 |access-date=2022-03-20}}</ref><ref name="Mats' Gun Page">{{Cite web |title=Articles on Bofors guns |url=http://www.tfd.chalmers.se/~m95perm/vapen/kanon/ |url-status=dead |archive-url=https://web.archive.org/web/20070608033931/http://www.tfd.chalmers.se/~m95perm/vapen/kanon/ |archive-date=2007-06-08 |access-date=2022-05-25 |website=tfd.chalmers.se }}</ref><ref name="t persson 40/60">{{Cite web |title=40 mm Luftvärnsautomatkanon m/36 |url=http://www.tfd.chalmers.se/~m95perm/vapen/kanon/div/40mm_akan_m36.html |url-status=dead |archive-url=https://web.archive.org/web/20070701070808/http://www.tfd.chalmers.se/~m95perm/vapen/kanon/div/40mm_akan_m36.html |archive-date=2007-07-01 |access-date=2022-05-25 |website=tfd.chalmers.se }}</ref> In some Bofors material the gun is standardized under the English name "Bofors 40&nbsp;mm Automatic Gun L/60".<ref name="Bofors 47 en"/>{{sfn|BuOrd, Vol. 4, p. 520}}

=== Calibre length ===
Contrary to the name, the Bofors 40&nbsp;mm Automatic Gun L/60 has an actual [[Caliber (artillery)#Barrel length|barrel length]] of 56.25 calibres – {{convert|2,250|mm|ftin|abbr=on}}. Due to this, the gun can at times be found under the designation ''L/56''.{{sfn|40 mm L/60 Model 1936 (NavWeaps 2016)}} The ''L/60'' calibre length – {{convert|2,400|mm|in|abbr=on}} – refers to the length of the barrel and [[Breechloader|breech]] mounted as a unit.<ref name="vr A 51">{{Cite book |url=https://libris.kb.se/bib/3352656 |title=Vapenregister för armén, 1951 år utgåva |publisher=Royal Swedish Army Materiel Administration |year=1951 |location=Sweden |language=Swedish |chapter=VII }}</ref> The gun has also been cited with a caliber length of ''L/62'' on occasion. This refers to the length of the barrel – 2,250&nbsp;mm – when equipped with the conical flash hider – {{convert|250|mm|ftin|abbr=on}}; amounting to a length of {{convert|2,500|mm|ftin|abbr=on}}, or 62.5 calibres.{{sfn|Swedish archives}} Similarly, the shorter ''L/43'' calibre length – {{convert|1,720|mm|ftin|abbr=on}} – refers to the length of the barrel and breech mounted as a unit.{{sfn|Swedish archives}} The actual barrel length is {{convert|1,570|mm|ftin|abbr=on}} – 39.25 calibres.{{sfn|Swedish archives}} With a flash hider or muzzle brake mounted the barrel length becomes {{convert|1,740|mm|ftin|abbr=on}}{{sfn|Swedish archives}} or {{convert|1,760|mm|ftin|abbr=on}}.<ref>{{Cite journal|date=1937|title=40 mm. autk. och 25 mm. ksp.|url=https://www.koms.se/tidskrift/arkiv/nr-1-1937/|journal=Tidskrift i Sjöväsendet|publisher=Kungliga Örlogmannasälskapet i Karlskrona|pages=18|archive-date=2 February 2022|access-date=2 February 2022|archive-url=https://web.archive.org/web/20220202202018/https://www.koms.se/tidskrift/arkiv/nr-1-1937/|url-status=live}}</ref>

== Development ==
In 1922, the [[Swedish Navy]] purchased a number of 40&nbsp;mm [[QF 2-pounder naval gun|2-pounder "pom-poms"]] from [[Vickers]] as anti-aircraft guns. The navy approached Bofors about the development of a more capable replacement, and Bofors signed a contract in late 1928. The company produced a gun that was a smaller version of a 57&nbsp;mm (6-pounder) semi-automatic gun, developed as an anti-[[torpedo boat]] weapon in the late 19th century by [[(Finspång (company)|Finspång]]. Bofors' first test gun was a re-barrelled [[Nordenfelt]] version of the Finspång gun, to which was added a semi-automatic loading mechanism.

Testing of the gun in 1929 showed that a problem existed with feeding the weapon to maintain a reasonable rate of fire. A mechanism that was strong enough to handle the stresses of moving the large [[cartridge (firearms)|round]] was too heavy to operate quickly enough to fire rapidly. One attempt to solve the problem used [[zinc]] shell cases that burned up when fired. However, that left heavy zinc deposits in the barrel and had to be abandoned. In the summer of 1930, experiments were conducted with a new test gun that did away with controlled feed and instead flicked the spent casing out the rear, after which a second mechanism reloaded the gun by "throwing" a fresh round into the open breech from the magazine. That improved firing rates to an acceptable level, so work on a prototype commenced soon after.

During that period, [[Krupp]] purchased a one-third share of Bofors. Krupp engineers began the process of updating the Bofors factories with modern equipment and metallurgy, but the 40&nbsp;mm project was kept secret.

[[File:Bofors 40mm AAgun manege suomenlinna 1.jpg|thumb|Finnish Bofors 40 mm. This gun mounts the original reflector sights, and lacks the gun shield found on British examples]]

The prototype was completed and fired in November 1931 and, by the middle of the month, it was firing strings of two and three rounds. Changes to the feed mechanism were all that remained and, by the end of the year, the gun was operating at 130 rounds per minute. The development needed to turn it into a weapon suitable for production was completed in October 1933. Because acceptance trials had been passed the year before, it became known as the "40&nbsp;mm akan M/32". Most forces referred to it as the "Bofors 40&nbsp;mm L/60", although the barrel was actually 56.25 [[caliber (artillery)|calibres]] in length, not the 60 calibres that the name implied.{{citation needed|date=April 2014}}

The gun fired a {{convert|900|g|lb|abbr=on}} [[high explosive]] shell at {{convert|2960|ft/s|m/s|abbr=on}} from a 40 × 311 rimmed cartridge.{{sfn|Johnson|1944|page=385}} The rate of fire was normally about 120 rounds per minute (2 rounds per second), which increased slightly when the barrels were closer to the horizon, because gravity assisted the feeding from the top-mounted magazine. Practical firing rates were closer to 80–100 rpm, because the rounds were fed into the breech from four-round clips which had to be replaced by hand. The maximum attainable ceiling was {{convert|7200|m|abbr=on}}, but the practical maximum was about {{convert|3800|m|abbr=on}}.

The gun was provided with an advanced sighting system. The trainer and layer were both provided with [[reflector sight]]s for aiming, while a third crew-member, standing behind them, "adjusted" for lead using a simple mechanical computer. Power for the sights was supplied from a 6[[Volt|V]] battery.

[[File:Bofors-p004596.jpg|thumb|British 40mm L/60 with Stiffkey Sight, being operated by the gun layer standing on the right. The layer operates the trapeze seen above the sights, moving them to adjust for lead. The loader stands to the layer's left, and the two trainer/aimers are sitting on either side of the gun.]]

In spite of the successful development, the Swedish Navy changed its mind and decided it needed a smaller hand-traversed weapon of 13&nbsp;mm-25&nbsp;mm size, and tested various designs from foreign suppliers. With the development of the 40&nbsp;mm well advanced, Bofors offered a 25&nbsp;mm version in 1932, which was eventually selected as the [[Bofors 25 mm M/32]].

The first version of the 40&nbsp;mm the Swedish Navy ordered was intended for use on submarines, because the larger calibre allowed the gun to be used both as an anti-aircraft gun, and against smaller ships. The barrel was shorter, at 43 calibres, which reduced the muzzle velocity to about {{convert|700|m/s|ft/s|abbr=on}}. When not in use, the gun was pointed directly up and retracted into a watertight cylinder. The only known submarines that used that arrangement were the [[HSwMS Sjölejonet (1936)|''Sjölejonet''-class]] boats. The guns were later removed when the submarines were modified with streamlined conning towers.

The first order for the "real" L/60 was made by the [[Royal Netherlands Navy|Dutch Navy]], which ordered five twin-gun mounts for the [[cruiser]] {{HNLMS|De Ruyter|1935|2}} in August 1934. Those guns were stabilized using the [[Hazemeyer gun mount|''Hazemeyer mount'']], in which one set of layers aimed the gun, while a second manually stabilized the platform the gun sat on. All five mounts were operated by one fire-control system.

Bofors also developed a towable carriage, which was displayed at a show in Belgium in April 1935. That mount allowed the gun to be fired from the carriage with no set-up required, although it had limited accuracy. If time was available for set-up, the gunners used the tow-bar and muzzle lock as levers, raising the wheels off the ground and so lowering the gun onto supporting pads. Two additional legs folded out to the sides, and the platform was then levelled with hand cranks. The entire set-up process could be completed in under a minute.

Orders for the land-based versions were immediate, starting with one for eight weapons from Belgium in August 1935, followed by a flood of orders from other forces including Poland, Norway, and Finland.{{sfn|40 ItK/35-39 B (jaegerplatoon.net)}}{{sfn|Encyclopédie des Armes|1986|p=1749}} It was accepted into the [[Swedish Army]] the next year, and known as the "40&nbsp;mm lvakan m/36", the lower-case "m" indicating an army model as opposed to the capital "M" for the navy.

=== Licensed production ===
Within a few years AB Bofors received number of orders, but more importantly at that time, a number of foreign governments negotiated for licensed production of the gun and its ammunition. These nations included Poland, Finland, Greece, Norway and many other countries.{{sfn|40 ItK/35-39 B (jaegerplatoon.net)}} Thus by 1939 Bofors gun was in production all over Europe for many armies in bewildering arrangement of cross-deals. For instance, the United Kingdom took out a license, but was in such a hurry to re-arm with the Bofors gun that it also purchased quantities from Poland and Hungary. France wanted to set up a line but purchased guns from Poland. Poland meanwhile developed its own version of Bofors gun, contributing a lighter carriage (in the '''40&nbsp;mm armata przeciwlotnicza Bofors wz. 36''') which was later adopted by the British.{{refn|name="Use by Other Nations (NavWeaps)"}}

The Swedish navy adopted the weapon as the m/36 in two versions: hand-worked single air-cooled, and power-operated twin water-cooled. A twin air-cooled mounting, probably hand-worked, was also used by the navies of Sweden and Argentina, and a twin air-cooled wet mounting was developed for Polish submarines.{{refn|name="Use by Other Nations (NavWeaps)"|{{harvnb|40 mm L/60 Model 1936 (NavWeaps)|page=[http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php#Use_by_Other_Nations Use by Other Nations]}} }}
{{clear left}}

== British versions ==
=== Army and RAF Regiment versions ===
[[File:QF 40mm Mk1 CFB Borden 1.jpg|thumb|Q.F. 40 mm Mk. 1 displayed at [[CFB Borden]]. This example mounts a Stiffkey Sight, and displays the additional armor protecting the gunners]]
[[File:HMS Isis Bofors gun, Tobermory, 1978.jpg|thumb|Bofors gun on the {{sclass2|Ley|minehunter}} {{HMS|Isis|M2010|6}} (1978)]]

The [[British Army]] had first examined the weapon in 1937, when it received a number of Polish-built examples for testing. They were known as the "QF 40&nbsp;mm Mark I" (QF standing for [[British ordnance terms#QF|"quick firing"]]). With a minor change to the [[flash suppressor|flash hider]], they were designated "Mark I/2". A production licence was acquired, and the gun was converted from [[metric system|metric]] to [[imperial unit|imperial]] measurements. Numerous changes were made to the design so that it was more suitable for mass production, because the original Bofors design was intended to be hand-assembled. Many parts were labelled "file to fit on assembly", requiring many man-hours of work to complete.

Testing showed that there was a serious problem with aiming the gun at high-speed aircraft. Although it could be trained quickly, aiming accurately while doing so proved difficult. In order to deal with that, the British introduced a complex [[analog computer|mechanical analogue computer]], the [[Kerrison Predictor|Kerrison Director]], which drove the laying electrically. A three-man team operated the director by pointing it at the target whilst dialing in estimates for speed, range, and various atmospheric conditions. The director then aimed the gun using powered mounts, while a gunner loaded the clips. That eliminated the need for the lead-correcting reflector sights, which were replaced with a backup system consisting of a simple ring-and-post sight, known as a "pancake".

In that form, the "QF 40&nbsp;mm Mark III" (Mk II was a designation used for [[QF 2 pounder naval gun#QF 2-pounder Mark II|a version of the naval "pom-pom"]] anti-aircraft gun), became the army's standard light anti-aircraft (AA) weapon, operating alongside their [[QF 3-inch 20 cwt|3-inch 20 cwt]] and [[QF 3.7-inch AA gun|3.7-inch]] heavy AA guns. British production started slowly and, by September 1939 only 233 equipments had been produced. However, by the end of the war, the total production of British, Canadian and Australian factories numbered over 19,000. The peak production year was 1942, when British factories produced 5,025 and Canadian factories produced 1,311.<ref>{{cite web|url=http://www.wwiiequipment.com/index.php?option=com_content&view=article&id=84:bofors-40mm-anti-aircraft-gun&catid=41:anti-aircraft&Itemid=58|title=Bofors 40mm Anti-Aircraft Gun|first=David|last=Boyd|website=www.wwiiequipment.com|access-date=13 March 2017|archive-url=https://web.archive.org/web/20170314152105/http://www.wwiiequipment.com/index.php?option=com_content&view=article&id=84:bofors-40mm-anti-aircraft-gun&catid=41:anti-aircraft&Itemid=58|archive-date=14 March 2017|url-status=live}}</ref>

In combat, it was found that the Kerrison was difficult to set up in many situations, as well as making [[logistics]] more complex, due to the need to keep its electrical generator supplied with fuel. In most engagements, only the pancake sights were used, without any form of correction, making the British versions less capable than those used by other forces. Eventually, an anti-aircraft gunnery school on the range at [[Stiffkey]] on the [[Norfolk]] coast, delivered a workable solution, a trapeze-like arrangement that moved the pancake sights to offer lead correction, operated by a new crew-member standing behind the left-hand layer. The "Stiffkey Sight" was sent out to units in 1943, arriving in Canadian units in the midst of the [[Battle of the Aleutian Islands]]. A final wartime change to the elevation mechanism resulted in the "QF 40&nbsp;mm Mark XII". A much lighter, two-wheeled carriage was also developed for [[airborne forces|airborne]] use.

The army experimented with various [[Self-propelled anti-aircraft weapon|self-propelled anti-aircraft guns]] based on various [[tank]] chassis. Changes to the breech for that role created the "QF 40&nbsp;mm Mark VI", which was used on the [[Crusader tank]] to produce the [[Crusader tank#Crusader III, AA Mk I|Crusader III AA Mark I]]. The main self-propelled version of the Bofors was the gun mounted on a chassis derived from the [[Morris C8]] "Quad" artillery tractor, which was known as the "Carrier, 30 cwt, SP, 4×4, 40 mm AA (Bofors)" or Morris-Commercial C9/B. Such guns were used in support of army divisions, to provide swift protection against air attack without the need to unlimber. They saw service in north-west Europe, where six SP Bofors of 92nd (Loyals) Light Anti-Aircraft Regiment, Royal Artillery, landed with the [[British 3rd Infantry Division]] on [[Sword Beach]] on D-Day, to protect the vital bridges over the [[Canal de Caen à la Mer|Caen Canal]] and the [[Orne River]] ([[Pegasus Bridge]] and [[Horsa Bridge]]), shooting down 17 German planes. Later in the campaign, SP Bofors were used extensively for ground shoots as well as in an anti-aircraft role.

In British Army service, the Bofors found a highly specialised role: during the [[North Africa campaign]], at the [[Second Battle of El Alamein]], they were used to fire [[tracer ammunition|tracer]] horizontally to mark safe paths for units through the German minefields. That practice was further developed during operations in north-west Europe, where bursts of colour-coded tracer were used to define the axis of advance of different formations in large-scale night attacks.

The [[RAF Regiment]] was formed in February 1942, in response to the German capture of airfields with airborne troops in the [[Battle of Crete]], which resulted in strategic defeat on the island by numerically inferior German forces. The formation of a dedicated airfield defence force included low-level air defence, in which the Bofors L60 — the same design as the Army version — was the principal weapon for the RAF Regiment's Light Anti-Aircraft squadrons in North Africa, Malta, Italy, the Balkans, the UK (including the allocation of fifty-two squadrons to [[Operation Diver]] defence against V-1 flying bombs in southern England), and north-western Europe (from [[Normandy landings]] through to the cessation of hostilities).

No 2875 Squadron RAF Regiment, employing the L60, became the first unit to shoot down a jet aircraft, a [[Messerschmitt Me 262]], with ground-based anti-aircraft fire, at [[Helmond]] in the Netherlands on 28 November 1944. Although the Allied air forces had achieved air superiority by the Normandy landings, [[Advanced Landing Ground]]s continued to be high-priority targets for the Luftwaffe when the opportunity presented, and that ensured that the RAF Regiment's L60s continued to be heavily used. For example, on New Year's Day 1945, during the [[Battle of the Bulge]], RAF Regiment Light Anti-Aircraft squadrons shot down 43 German aircraft and damaged 28 others during the [[Operation Bodenplatte]] attacks on eleven RAF forward airfields. There were insufficient guns available to equip the RAF Regiment squadrons in the Far East during the war, and they had to make do mostly with [[Hispano-Suiza HS.404|20 mm Hispano]] and [[Oerlikon 20 mm cannon|Oerlikon 20 mm]] guns.{{Citation needed|date=March 2022}}

A Light Anti-Aircraft field regiment (one with each infantry division) had 54 Bofors guns.{{sfn|TM 30-410|page=33}}

After World War II, the RAF Regiment continued to employ the L60 as its principal anti-aircraft weapon until it was replaced by the L70 gun in 1957. The guns were deployed in the UK, Germany, Cyprus, the Middle East, and the Far East.

=== Naval versions ===
[[File:Boffin 40mm bofors cfb borden 1.jpg|thumb|upright|Single Bofors 40 mm Boffin mounting, displayed at [[CFB Borden]]. In 1996, museum pieces like this cannon were pressed back into service as the main armament of the [[Kingston class minesweepers|''Kingston''-class minesweepers]].<ref name=CASRKingstonClass2>{{cite web |url=http://casrca.nationprotect.net/id-mcdv-midlife-2.htm |title=The Kingston Class: 'Mid-Life' or Move Over for the MCDV? |publisher=[[Canadian American Strategic Review]] |last=Priestley |first=Stephen |access-date=2012-01-09 |date=June 2006 |quote=<!-- Among MCDV inadequacies, armament is listed as the major limitation for sovereignty patrol duties. The ''Kingston'' class are armed with twin 12.7 mm M2HB machine guns on either side of the bridge but the main armament is a 40mm L/60 Bofors. This gun is a museum piece dating back to 1944. Even as a training weapon, the Bofors is of dubious value – it was just that they were just on hand and lowered costs. --> |url-status=dead |archive-url=https://web.archive.org/web/20131203015054/http://casrca.nationprotect.net/id-mcdv-midlife-2.htm |archive-date=3 December 2013}}</ref>]]

The [[Royal Navy]] also made extensive use of the Bofors. Its first examples were air-cooled versions quickly adapted for ships during the [[Norway campaign|withdrawal from Norway]]. After the [[German invasion of the Netherlands]] in May 1940, the Dutch minelayer, [[HNLMS Willem van der Zaan (ML-2)|HNLMS ''Willem van der Zaan'']], gave the navy its first example of a water-cooled gun on its Hazemeyer tri-axially stabilized mounting. Locally produced examples started arriving in 1942, known as the "QF 40&nbsp;mm Mark IV" with twin-mounts, or the "QF 40&nbsp;mm Mark V" with single mounts. The navy ran through a variety of versions of the basic Bofors gun over the war, including the Mark VII to Mark XI. The British light anti-aircraft weapon already in use with the Royal Navy's, the [[QF 2 pounder naval gun|QF 2-pounder gun]], also had a calibre of 40&nbsp;mm, but was referred to as the QF 2-pdr.

In the Royal Navy guns and mounts were designated separately. The following mountings were used:
* Mark I: twin mounting based on American design and using American-built guns, not widely fitted. Fitted for remote [[fire-control system|fire control]].
* Mark II: quadruple version similar to the Mark I
* Mark III: a navalized version of the Army single mounting, hand worked elevation and training.
* Mark IV: a tri-axially stabilized twin mounting, copied from, and usually known as, the "Hazemeyer". It had on-mounting fire control, and was usually fitted with Radar Type 282 to provide target range information.
* Mark V: twin mounting, which superseded, and eventually replaced, the Mark IV, often referred to as the "utility" mounting. It was a simplified, unstabilised mounting based on the American twin mounting Mark I, and was designed for remote fire control.
* Mark VI: a six-barreled weapon, feeding from large trays instead of clips, and designed for remote control from a dedicated radar-equipped director.
* Mark VII: a single-barreled, hydraulically-powered mounting, that superseded the Mark III and entered service in 1945.
* Mark IX: Mark VII mount modified for electrical power, as the Mounting Mark IX and, in that form, saw service in the [[Falklands War]].

The Mounting Mark V (Mark VC for Canadian built examples) for the 20&nbsp;mm Oerlikon and QF 2 pounder guns was also adopted initially as an interim mount for the Bofors. It was a single-barrelled mounting with hydraulic power, and was known as the "Boffin".

The final British Bofors mounting to see service was the "Stabilized Tachymetric Anti-Aircraft Gun" (STAAG), which was twin-barrelled, stabilised, and carried its own [[Tachymetric anti-aircraft fire control system|tachymetric]] (i.e. predictive) fire control system, based around the centimetre Radar Type 262, capable of "locking on" to a target. The mounting was heavy (17.5 tons) and the high-vibration of the gun mounting made it a poor location for sensitive valve electronics and mechanical computers. The STAAG Mark I carried the radar dish over the gun barrels, where it was subject to damage during firing so, on the STAAG Mark II, the set was shifted to the roof of the control cabin. STAAG was ultimately too difficult to maintain in the harsh environment of a warship and was replaced by the Mounting Mark V, with the fire control equipment located remotely, then by the single Mark VII and, ultimately, with the [[Seacat (missile)|GWS20 Seacat missile system]]. The final version of STAAG was fitted to the RN [[Whitby class frigate|Type 12 ''Whitby''-class]] anti-submarine frigates and the [[Leopard-class frigate|Type 41 ''Leopard'']] anti-aircraft and [[Salisbury-class frigate|Type 61 ''Salisbury'']] air direction frigates, completed from 1956 to 1958. The cruiser [[HMNZS Royalist|''Royalist'']] was also fitted with the STAAG Mk 2 during modernisation before transfer to the RNZN in the 1950s. Initially, it had three STAAG CIWS, the STAAG in Q position was removed in 1960, but it carried two mounts until the end of its service in [[Southeast Asia]]n waters, in 1965. In 1956 during the [[Suez Crisis]], the crew of ''Royalist'' seemed to find the STAAG a reasonably effective anti-aircraft weapon in [[Operation Musketeer (1956)|Operation Musketeer]].

== U.S. versions ==
=== Manufacturing ===
In order to supply both the U.S. Army and U.S. Navy with much greater numbers of the guns, [[Chrysler]] built 60,000 of the guns and 120,000 barrels through the war,<ref name="FW"/> at half the original projected cost, and filling the Army's needs by 1943.<ref name="allpar">{{cite journal |url=http://www.allpar.com/history/military/bofors.html |title=Chrysler Corporation, Gun Maker: Bofors Guns of World War II |journal=Allpar |access-date=2010-11-04 |archive-url=https://web.archive.org/web/20101107194948/http://www.allpar.com/history/military/bofors.html |archive-date=7 November 2010 |url-status=live }}</ref> Over the lifetime of the production, their engineers introduced numerous changes to improve mass production, eventually halving the overall time needed to build a gun. Most of the changes were in production methods rather than the design of the gun itself: for example, milling from steel block was replaced by stampings and castings whenever possible, and Amplex division of Chrysler (which normally manufactured [[oilite]]) produced nine parts by [[sintering]].<ref name="allpar" /><ref>{{citation |last=Borth |first=Christy |title=Masters of Mass Production |publisher=Bobbs-Merrill Company |location=Indianapolis |date=1945 |pages= 164–165, 197, 200–204}}</ref> York Safe & Lock also produced the weapons, though its attempts to coordinate drawings across the program were unsuccessful, and this responsibility was transferred to the [[Naval Gun Factory]] in July 1943.<ref name=BuOrd1/>

There were many difficulties in producing the guns within the United States, beyond their complexity (2,000 subcontractors in 330 cities and 12 Chrysler factories were used to make and assemble the parts). The drawings were metric, in Swedish, with loose tolerances for hand fitting and read from the [[Multiview orthographic projection|first angle of projection]]. Chrysler had to translate to imperial measures and English language, fix absolute dimensions, and mirror/reorder the drawings to the third angle of projection. Chrysler engineers also tried to simplify the gun, unsuccessfully, and to take high-speed movies to find possible improvements, but this was not possible until near the end of the war.<ref name="allpar" />

<blockquote>Swedish blueprints had many notes on them such as "file to fit at assembly" and "drill to fit at assembly," all of which took much production time in order to implement. Thirdly, the Swedish mountings were manually worked, while the USN required power-worked mountings in order to attain the fast elevation and training speeds necessary to engage modern aircraft. Fourthly, the Swedish guns were air-cooled, limiting their ability to fire long bursts, a necessity for most naval AA engagements. Finally, the USN rejected the Swedish ammunition design, as it was not boresafe, the fuze was found to be too sensitive for normal shipboard use and its overall design was determined to be unsuitable for mass production.{{sfn|40 mm L/60 Model 1936 (NavWeaps 2011)}}<ref name=BuOrd1/></blockquote>

=== Naval ===
[[File:Bofors firing USS Hornet.jpg|thumb|A MK 12 quadruple mount of Bofors guns fires from {{USS|Hornet|CV-12|6}}]]
<!-- Deleted image removed: [[File:M5 director.jpg|thumb|M5 gun director 1944]] -->
The [[United States Navy]]'s [[Bureau of Ordnance]] purchased a twin-mount air-cooled example, spare parts and 3,000 rounds of ammunition directly from Bofors, which arrived in New York on 28 August 1940 aboard the Army transport {{USAT|American Legion}}, which had evacuated 897 people, including members of the Norwegian royal family, through the Finnish port of [[Pechengsky District|Petsamo]].<ref>{{cite web |url=https://www.history.navy.mil/research/histories/ship-histories/danfs/a/american-legion.html |title=''American Legion'' |author=Naval History And Heritage Command |work=Dictionary of American Naval Fighting Ships |publisher=Naval History And Heritage Command |access-date=10 August 2015 |archive-url=https://web.archive.org/web/20150924143341/http://www.history.navy.mil/research/histories/ship-histories/danfs/a/american-legion.html |archive-date=24 September 2015 |url-status=live }}</ref> During that month another Dutch ship, the [[HNLMS Van Kinsbergen (1939)|''Van Kinsbergen'']], demonstrated the Hazemeyer mount to Navy observers. The gun was quickly chosen as the Navy's standard anti-aircraft weapon over the British 40&nbsp;mm calibre, [[2-pounder pom-pom]]; however, negotiations with Bofors for licensed production stalled when the Swedes requested airplane export and manufacturing licenses in return.<ref name=BuOrd1>{{cite book |last=Rowland |first=Buford |author2=Boyd, William |title=US Navy Bureau of Ordnance in World War II |publisher=US Navy Bureau of Ordnance, Department of the Navy |year=1954 |pages=219–230 |location=Washington, DC |url=https://catalog.hathitrust.org/Record/007884814 |access-date=29 September 2016 |archive-url=https://web.archive.org/web/20161010153503/https://catalog.hathitrust.org/Record/007884814 |archive-date=10 October 2016 |url-status=live }}</ref> Reportedly, the Navy secretly imported a set of [[imperial units|imperial]] designs from Britain and started production illegally. A formal contract with Bofors was reached in June 1941. The resulting Mark 1 and Mark 2 weapons were intended for the left and right side of a twin mount, respectively, and were adapted by Chrysler for water cooling.<ref name="allpar" />
[[File:40MM Bofors Anti-Aircraft Gun, Patriots Point.jpg|thumb|A twin Bofors 40 mm at [[Patriots Point]]]]
Following the [[attack on Pearl Harbor]] on 7 December 1941, the existing [[1.1"/75 caliber gun|1.1" (28 mm) quad mount]] and [[.50 caliber machine gun]]s were determined to be inadequate against modern aircraft, and their replacement by 40&nbsp;mm Bofors and [[20 mm Oerlikon]] weapons was accelerated. The water-cooled version was used almost exclusively by the U.S. Navy and Coast Guard. The 40&nbsp;mm quadruple mount was developed by essentially mounting two twin mounts side by side.<ref name=BuOrd1/> A major improvement was the addition of power operation to both twin and quadruple mounts. Essentially all US naval mountings were twin or quadruple. 40&nbsp;mm weapons were eventually mounted on virtually every naval and armed auxiliary vessel larger than a small landing craft.<ref name=BuOrd1/> After the war, the [[3"/50 caliber gun]] Mark 27 twin mount began to replace the Bofors, because the "VT" [[proximity fuse]] would not fit a 40mm projectile, and the 40&nbsp;mm weapon was considered inadequate against the emerging [[anti-ship missile]] threat. The twin 3" mount was intended to be the same weight as the 40mm quad mount, but was somewhat heavier in practice, which had to be compensated for. Except on destroyers and new construction, the Navy was slow in phasing out the 40&nbsp;mm gun, and it continued in active Navy service through the Korean War. It remained on inactive [[Reserve fleet]] ships at least through the early 1970s.<ref>{{cite book |last=Friedman |first=Norman |author-link=Norman Friedman |title=U.S. Destroyers: An Illustrated Design History |pages=130–131 |publisher=Naval Institute Press |year=2004 |location=Annapolis |isbn=1-55750-442-3|edition=Revised }}</ref>

The Navy's satisfaction with the weapons was demonstrated by their practice of telegraphing Chrysler Corporation with the serial numbers of guns when they shot down an aircraft.<ref name="allpar" />

=== Army ===
[[File:40mm M1 Automatic Gun (A-A), & M2(A1) Carriage FRONT TM9-252 fig002.jpg|thumb|U.S. Army 40 mm Automatic Gun, Anti-Aircraft, M1, on 40 mm Gun Carriage M2(A1).{{sfn|TM 9-252}}]]
In 1938 the [[United States Army]] introduced a [[37 mm Gun M1|37&nbsp;mm gun]] of their own design, but found it to be of limited performance. In early World War II, six British Bofors were imported for testing, along with Kerrison Predictor [[director (military)|directors]], and they proved to be superior in all areas. By the middle part of the war, most of the 37&nbsp;mm guns had been replaced by the 40&nbsp;mm.In U.S. Army and Marine Corps service, the single mount Bofors was known as the '''40&nbsp;mm Automatic Gun M1'''.{{sfn|Encyclopédie des Armes|1986|p=1753}} The U.S. version of the gun fired three variants of the British Mk. II high-explosive shell as well as the M81A1 armor-piercing round, which was capable of penetrating some 50&nbsp;mm of homogeneous armor plate at a range of 500 yards.
In the Army, each Anti-Aircraft Artillery (AAA) auto-weapons battalion was authorized a total of thirty-two 40&nbsp;mm guns in its four firing batteries.<ref>{{cite web|url=http://www.militaryresearch.org/44-25%2022Apr44.pdf|title=TO&E 44-25, AAA Auto-Weapons Battalion, Mobile|website=militaryresearch.org|access-date=29 September 2016|archive-url=https://web.archive.org/web/20161010153526/http://www.militaryresearch.org/44-25%2022Apr44.pdf|archive-date=10 October 2016|url-status=live}}</ref><ref>{{Cite web |url=http://www.385th.com/ |title=385th AAA Auto-Weapons Battalion website |access-date=29 September 2016 |archive-url=https://web.archive.org/web/20161009195815/http://www.385th.com/ |archive-date=9 October 2016 |url-status=usurped}}</ref> Each U.S. Marine division had a "special weapons battalion" that included sixteen 40&nbsp;mm guns; in early 1944 these were replaced with anti-aircraft battalions with twelve 40&nbsp;mm guns. [[Marine defense battalions]] also used the 40&nbsp;mm gun.<ref>{{cite web|url=http://www.ww2gyrene.org/special_weapons_battalion.htm|title=Divisional Special Weapons Battalion at Gyrene.org|website=ww2gyrene.org|access-date=29 September 2016|archive-url=https://web.archive.org/web/20161025201404/http://www.ww2gyrene.org/special_weapons_battalion.htm|archive-date=25 October 2016|url-status=live}}</ref> All of these unit types also included other AA weapons.

During World War II, the twin mount version of the gun was mounted on an [[M24 Chaffee]] tank chassis as the [[M19 Gun Motor Carriage]]. In the 1950s, the [[M41 Walker Bulldog]] tank was heavily modified into the [[M42 Duster]] with the same twin 40&nbsp;mm mounting. After being largely withdrawn from service in the early 1960s, the M42 was re-introduced beginning in 1966 for the [[Vietnam War]], where it was mostly used for ground fire support. Following the withdrawal from Vietnam in the early 1970s, the M42 was retained in [[Army National Guard|National Guard]] service until finally retired in 1988.

== Captured examples ==
In World War II Germany, the ''[[Wehrmacht]]'' used a number of Bofors guns which had been captured in Poland and France. The ''[[Kriegsmarine]]'' also operated some guns obtained from Norway. In German naval use, the gun was designated the '''"4&nbsp;cm FlaK 28"''', and was variously used aboard individual examples of many different classes of warship, including but not limited to; the cruisers ''[[German cruiser Admiral Hipper|Admiral Hipper]]'' and ''[[German cruiser Prinz Eugen|Prinz Eugen]]'' toward the end of the war; M1940-class minesweeper; ''vorpostenboot''.{{sfn|Campbell|1985|page=254}} Beginning in 1942, several 'S 38 type' ''schnellboote'' were equipped with the Flak 28, enabling them to fight against British MGBs and MTBs on equal terms.

Germany also purchased a large number (200+) of [[MÁVAG|Hungarian-made]] Bofors guns. In return, Hungary received a [[7.5 cm Pak 40|75 mm PaK 40 gun]] for every 4-5 Bofors. The Wehrmacht used Hungarian guns after [[German invasion of Hungary (1944)|German occupation of Hungary]] from late 1944. Most of them were lost during the fights in [[Siege of Budapest|Budapest]] and [[Operation Spring Awakening|Transdanubia]].<ref>{{Cite book|title=A Magyar Királyi Honvédség légvédelme 1920-1945|last=Barczy|first=Zoltán|publisher=Zrínyi|year=2010|isbn=9789633274989|location=Budapest}}</ref>

Japan captured a number of Bofors guns in [[Singapore]]<ref>{{Cite book |last=Lardas |first=Mark |url=https://books.google.com/books?id=y3AqEAAAQBAJ&dq=Japan+captured+a+number+of+Bofors+guns+in+Singapore&pg=PA76 |title=B-25 Mitchell vs Japanese Destroyer: Battle of the Bismarck Sea 1943 |date=2021-12-23 |publisher=Bloomsbury Publishing |isbn=978-1-4728-4518-4 |language=en}}</ref> and put them into production as the Type 5.{{sfn|40mm/60 Type 5}}

== Service use ==
=== Bofors 40 mm Automatic Gun L/43 ===
The Bofors 40&nbsp;mm L/43 is a [[submarine]] variant of L/60 with retractable mounting, and using low propellant charge ammunition.{{sfn|40 mm L/60 Model 1936 (NavWeaps 2016)}}{{sfn|Bofors 40 mm L/43}}<ref name="urlBOFORS AUTOMATIC CANNON">{{cite web |first=Anthony G |last=Williams |url=http://www.quarryhs.co.uk/Bofors.htm |title=Bofors Automatic Cannon |archive-url=https://web.archive.org/web/20121228005723/http://www.quarry.nildram.co.uk/Bofors.htm |archive-date=28 December 2012 |url-status=dead|work=Military Guns & Ammunition |date=2011 }}</ref>

=== Bofors 40 mm Automatic Gun L/60 ===
[[File:HMCS Nanaimo Bofors.jpg|thumb|right|The L/60 Bofors fitted to the {{sclass|Kingston|coastal defence vessel|2}} {{HMCS|Nanaimo|MM 702|6}}]]
[[File:40mm-twin-naval.jpg|thumb|right|Twin L/60 dismounted from an Argentinian {{sclass|Drummond|corvette|1}} which saw service during the Falklands War]]
[[File:HMAS Sydney Bofors guns.jpg|thumb|right|Gunnery practice on the aircraft carrier {{HMAS|Sydney|R17|6}} off Korea in 1951]]
The L/60 remained in front-line service well into the 1980s and 1990s although it had been replaced in production by the [[Bofors 40 mm Automatic Gun L/70]]. In most cases, these were the ground anti-aircraft versions, as a suitable replacement in this role did not come along until the introduction of truly effective [[MANPADS]] missiles in the 1980s and 1990s.{{citation needed|date=January 2022}}

In United States Army service, the [[M19 Gun Motor Carriage]] was replaced by the [[M42 Duster]], using the same turret but based on the chassis of the [[M41 Walker Bulldog]] tank.<ref>{{Cite book |last=Doyle |first=David |url=https://books.google.com/books?id=sDgxEAAAQBAJ&dq=M19+Gun+Motor+Carriage+was+replaced+by+the+M42+Duster&pg=PA174 |title=Vehicles and Heavy Weapons of the Vietnam War |date=2021-08-31 |publisher=Pen and Sword Military |isbn=978-1-5267-4367-1 |language=en}}</ref>

The L/60 saw active service with the Argentinian and British navies in the 1982 [[Falklands War]] and continued to be used into the 1990s, when it was replaced by modern 20&nbsp;mm and 30&nbsp;mm artillery.{{Citation needed|date=June 2023}}

The [[Canadian Forces]] removed the guns from their surface fleet in the late 1980s when they were considered to be outdated, only to re-use old Bofors guns as the main armament of the {{sclass|Kingston|coastal defence vessel|2}}.<ref name=CASRKingstonClass2/> The Bofors served as the main armament for almost 20 years.<ref name=Nord2017-05-16/> The decision to remove them was made in 2014, due to their maintenance burden, and their lack of stabilization.{{Citation needed|date=June 2023}}

As of August 2006, the French navy uses L/60s on more than twenty ships (patrols and auxiliaries).{{Citation needed|date=June 2023}}

Ships of the [[Norwegian Coast Guard|Norwegian]] and [[Icelandic Coast Guard]]s continue to use the 40mm Bofors gun.{{Citation needed|date=June 2023}}

The L/60 continued in use in the [[Irish Army]] until recent years, when it was retired in favour of the radar-controlled L/70. The [[Irish Naval Service]] P20 class retained L/60s on board as their main weapon until the 1990s but were rearmed with L/70s. The last remaining P20-class patrol vessel, ({{ship|LÉ|Aisling|P23|6}}) decommissioned in 2016, was the final vessel fitted with the L/70. Two retired L/60s can be seen adjacent the square in Sarsfield Barracks, Limerick.{{Citation needed|date=June 2023}}

The last 40&nbsp;mm L/60 Bofors in service with the [[Royal Australian Navy]] (RAN) were used as the main weapon aboard the {{sclass|Attack|patrol boat|0}} and {{sclass|Fremantle|patrol boat|0}} patrol boats and for training purposes at the West Head gunnery range at {{HMAS|Cerberus|naval base|6}}.<ref name=lastblast>{{cite news|url=http://www.navy.gov.au/w/index.php/Last_blast_for_Bofors |title=Last blast for Bofors |year=2007 |publisher=Royal Australian Navy |access-date=2009-09-14 |url-status=dead |archive-url=https://web.archive.org/web/20110613233736/http://www.navy.gov.au/w/index.php/Last_blast_for_Bofors |archive-date=13 June 2011 }}</ref> These were removed from service during 2007; Bofors were used aboard almost every RAN ship to operate between the 1940s and the 1990s, including the aircraft carriers [[HMAS Sydney (R17)|''Sydney'']] and [[HMAS Melbourne (R21)|''Melbourne'']].<ref name=lastblast/>

In 2012, the L/60 was still being used by Brazil, Indonesia, Paraguay, Taiwan, and the United States.

==== AC-130 Gunship ====
[[File:Bofors guns on Spectre gunship.jpg|thumb|Bofors guns on an AC-130A Spectre gunship]]
[[File:23-04-177-40mm-gun.jpg|thumb|Bofors 40 mm L/60 gun on display at the [[Museum of Aviation (Warner Robins)|Museum of Aviation]]. This gun was mounted in a [[Lockheed AC-130|AC-130U]].]]

Since the beginning of the 1970s, the 40&nbsp;mm Bofors L/60s have been used in the [[United States Air Force]]'s [[Lockheed AC-130]] gunships in the [[Close air support|air-to-ground]] role.<ref name=gunships>{{cite book|url=https://books.google.com/books?id=2h1dYiEC9jcC|title=Development and Employment of Fixed-Wing Gunships, 1962–1972|year=1982|publisher=Office of Air Force History, United States Air Force |access-date=2013-10-11|isbn=9781428993648}}</ref> Between 2006 and 2012, there were plans to remove these and the 20&nbsp;mm [[M61 Vulcan]]s from newer AC-130U variants and replace them with 30&nbsp;mm autocannons. However, these plans did not come to fruition at the time, and the 40&nbsp;mm Bofors and 20&nbsp;mm Vulcans remained in service {{As of|2009|lc=y}},<ref name=replacement>{{cite news|url=http://www.defenseindustrydaily.com/a-spookier-spooky-30mm-at-a-time-03023/|title=A Spookier Spooky, 30mm at a Time? Nope.|year=2009|work=Defense Industry Daily|access-date=2013-10-11|archive-url=https://web.archive.org/web/20130921043205/http://www.defenseindustrydaily.com/a-spookier-spooky-30mm-at-a-time-03023/|archive-date=21 September 2013|url-status=live}}</ref> though the later W- and upcoming J-model variants have 30&nbsp;mm [[Mk44 Bushmaster II]] autocannons instead.{{sfn|AC-130W Stinger II (USAF)}}{{sfn|AC-130J Ghostrider (USAF)}}

When four additional AC-130Us were to be converted from 2002, the necessary 40&nbsp;mm L/60 guns had to be salvaged from old M42 targets at the Nellis AFB range.<ref name=salvage>{{cite news|title=Air Commando Journal, Summer 2012, p. 22}}</ref> The final 40&nbsp;mm L/60 guns in US service were retired in 2020 with the last of the AC-130Us.

==Manufacturers==
* [[Bofors|AB Bofors]] (1932–2000)
* [[Zastava Arms]] (1970–present)
* [[Gun Carriage Factory Jabalpur]] (1960–present)
* [[United Defense]] Industries (2000–2006)
* [[BAE Systems AB]] (2006–present)

==Variants==
===Gun variants===
;Swedish variants{{sfn|40 mm L/60 Model 1936 (NavWeaps)|page=[http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php#Development_by_Bofors Development by Bofors]}}
* '''Bofors 40&nbsp;mm L/60 Model 1932''' — Unofficial designation of the prototype gun, made for Swedish Navy's official trials.
** '''Bofors 40&nbsp;mm L/43 Model 1932''' — A short-barrel version for submarines that was to be stowed in a waterproof tubular container located in the conning tower or under the decking.
* '''Bofors 40&nbsp;mm L/60 Model 1934''' — Improved model, exported to several countries but not adopted by the Swedish military.
* '''Bofors 40&nbsp;mm L/60 Model 1936''' — Slightly further improved model adopted by the Swedish military, as well as other countries.
;US variants{{sfn|40 mm L/60 Model 1936 (NavWeaps)|page=[http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php#Use_by_USA Use by USA]}}
* '''40&nbsp;mm L/56 Mark 1''' / '''40&nbsp;mm L/56 Mark 2''' — US Navy water-cooled variants with interchangeable barrel assemblies.{{efn|The '''Mark 1''' was a left-hand weapon, while the '''Mark 2''' was a right-hand weapon. Except for the barrel assemblies, the components were not interchangeable.}} Both were used for all twin and quad mountings.
* '''40&nbsp;mm L/56 M1''' — US Army air-cooled version. Barrel assemblies were interchangeable with British and Canadian Bofors guns. US Navy used a modified version for single mountings.

===Carriage variants===
;US variants

== Users ==
[[File:Finnish Bofors.jpg|thumb|right|Finnish soldiers operating the Bofors 40 mm gun during the [[Continuation War]].]]
[[File:Bofors 40mm L-60 gun Users.png|thumb|Map with users of the L/60 in blue]]
{{div col|colwidth=33em}}
* {{ALG}}<ref name="MF"/>
* {{ARG}}{{sfn|Military Balance 2016|p=376}}
* {{AUS}}<ref name="MF"/>
* {{AUT}}<ref name="MF"/>
* {{BAN}}<ref name="MF"/>
* {{BEL}}<ref name="MF"/>
* {{BIH}}{{sfn|Military Balance 2016|p=81}}
* {{BLZ}}<ref name="MF"/>
* {{BRU}}<ref name="MF"/>
* {{CAM}}<ref name="MF"/>
* {{CAN}} — L/60 Bofors (''Boffin'')<ref name="Wiener 1987">{{cite book|title=The armies of the NATO nations: Organization, concept of war, weapons and equipment|series=Truppendienst Handbooks Volume 3|year= 1987|first=Friedrich |last=Wiener |pages=524–525|publisher=Herold Publishers|location=Vienna}}</ref> used by the [[Royal Canadian Navy]] on 12 [[Kingston-class coastal defence vessel]]s
* {{CHA}}<ref name="Chad">{{cite magazine|title=Tchad: le désert des Tartares|first=Pierre|last=Darcourt|pages=16–19|magazine=La Gazette des armes|language=fr|url=http://fr.1001mags.com/parution/gazette-des-armes/numero-125-janvier-1984/page-16-17-texte-integral|issue=125|date=January 1984|access-date=18 October 2018|archive-url=https://web.archive.org/web/20181019041136/http://fr.1001mags.com/parution/gazette-des-armes/numero-125-janvier-1984/page-16-17-texte-integral|archive-date=19 October 2018|url-status=live}}</ref>
* {{CHI}}<ref name="MF"/>
* {{CRO}}<ref name="MF"/>
* {{COL}} — M1A1 Bofors{{sfn|Military Balance 2016|p=390}}
* {{flaglist|Democratic Republic of the Congo}} — L/60{{sfn|Military Balance 2016|p=441}}
** {{flag|Katanga}} — Known as ''Beaufort''<ref>{{cite book|title=Modern African Wars: The Congo 1960–2002|last=Abbot|first=Peter|location=Oxford|publisher=[[Osprey Publishing]]|date=February 2014|isbn=978-1782000761|page=14}}</ref>
* {{CYP}} — M1 Bofors{{sfn|Military Balance 2016|p=87}}
* {{CZE}}
* {{flag|Denmark}} — Obtained manufacturing licenses during the 1930s for the L/60, but production never started.{{refn|name="Use by Other Nations (NavWeaps)"}} After World War II, Bofors L/60 guns were obtained.<ref name="Wiener 1987"/>
* {{DOM}}
* {{ECU}} — M1A1{{sfn|Military Balance 2016|p=396}}
* {{EGY}}<ref name="MF"/>
* {{EST}} — Used by the air defence artillery group and on submarines
* {{FIN}} — L/60 built under license before WW2{{sfn|40 ItK/35-39 B (jaegerplatoon.net)}}{{sfn|Encyclopédie des Armes|1986|p=1749}}
* {{FRA}}{{sfn|Encyclopédie des Armes|1986|p=1749}}
* {{GAM}}<ref name="MF"/>
* {{flag|Nazi Germany|name=Germany (Nazi)}} — Used captured examples as the '''4&nbsp;cm FlaK 28'''.{{sfn|Campbell|1985|page=254}}
* {{GER}}
* {{GEO}} — Used on Coast Guard ships and vessels
* {{GUA}}<ref name="MF"/>
* {{flag|Kingdom of Greece|name=Greece (1935–1973)}} — Obtained manufacturing licenses during the 1930s,{{sfn|Encyclopédie des Armes|1986|p=1749}} but production never started.{{refn|name="Use by Other Nations (NavWeaps)"}} M1 Bofors also used.<ref name="Wiener 1987"/>
* {{GRE}} — M1 Bofors.<ref name="Wiener 1987"/>
* {{flagcountry|Kingdom of Hungary}} — L/60 built under license as the '''4&nbsp;cm 36M Légvédelmi Gépágyú''' (''4 cm 36M Anti-Aircraft Machine Gun''). Also used to armed [[40M Nimród]] [[Self-propelled anti-aircraft weapon|SPAAG]].{{sfn|Encyclopédie des Armes|1986|p=1749}}
* {{IND}}{{sfn|Military Balance 2016|pp=257–258}}
* {{flaglist|Israel}}<ref name="MF"/>
* {{IRL}}{{sfn|Military Balance 2016|p=109}} — Taken out of use in 2016 on decommissioning of last naval vessel using it.{{citation needed|date=November 2018}}
* {{IRQ}}<ref name="MF"/>
* {{ITA}} — Bofors M1 used under designation ''Cannone contraereo 40/60''.<ref name="Wiener 1987"/>
* {{CIV}}{{sfn|Military Balance 2016|p=439}}
* {{JPN}}<ref name="MF"/>
* {{JOR}}<ref name="MF"/>
* {{ROK}} — L/60 and M1 variants{{sfn|Military Balance 2016|p=268}}
* {{LBN}}<ref name="MF"/>
* {{LBY}}<ref name="MF"/>
* {{LAT}}<ref>{{cite journal|title=The military situation in the Baltic States|first=Edgars|last=Andersons|year=2001|issue=6|volume=2001|journal=Baltic Defence Review|url=http://www.bdcol.ee/files/docs/bdreview/10bdr601_backup.pdf|pages=113–153|access-date=23 January 2019|archive-url=https://web.archive.org/web/20190124041412/http://www.bdcol.ee/files/docs/bdreview/10bdr601_backup.pdf|archive-date=24 January 2019|url-status=live}}</ref>
* {{LTU}}<ref name="MF"/>
* {{MEX}}<ref name="MF"/>
* {{MLT}}<ref name="MF"/>
* {{MNE}}
* {{MYA}} — M1 Bofors{{sfn|Military Balance 2016|p=276}}
* {{flaglist|Nepal}} — 2 L/60 guns{{sfn|Military Balance 2016|p=277}}
* {{flag|Nicaragua}} — 6 to 8 M1A1 guns
* {{NGR}}<ref name="auto">{{cite book|last=Jowett|first=Philip|title=Modern African Wars (5): The Nigerian-Biafran War 1967-70|year=2016|publisher=[[Osprey Publishing]] Press|location=Oxford|isbn=978-1472816092|page=20}}</ref>
:* {{flag|Biafra}} — Used guns captured from [[Nigerian Army]].{{sfn|Jowett|2016|p=24}}
* {{flaglist|Norway}} — L/60 built under license before WW2,{{sfn|Encyclopédie des Armes|1986|p=1749}} Bofors M1
* {{NZ}}<ref name="MF"/>
* {{OMN}}{{sfn|Military Balance 2016|p=347}}
* {{PAK}}{{sfn|Military Balance 2016|p=280}}
* {{PAN}}<ref name="MF"/>
* {{flaglist|Papua New Guinea}}
* {{PAR}} — M1A1 and L/60{{sfn|Military Balance 2016|p=408}}
* {{PER}} — 24 Bofors L/60, originally ordered by Spain but not delivered due to the civil war.<ref name="BB72">{{cite magazine|title=Blindorama: Pérou 1936–1945|magazine=Batailles et Blindés|issue=72|date=April 2015|pages=12–13|last=Mahé|first=Yann|language=fr}}</ref>
* {{PHI}}<ref name="MF"/>
* {{flagcountry|Second Polish Republic}} — L/60 built under license as '''40-mm armata przeciwlotnicza Bofors wz. 36'''{{sfn|Encyclopédie des Armes|1986|p=1749}}{{refn|name="Use by Other Nations (NavWeaps)"}}
* {{POR}} — M1<ref name="Wiener 1987"/>
* {{QAT}}<ref name="MF"/>
* {{flagcountry|Kingdom of Romania}} — 54 pieces delivered by Germany during the first half of World War II{{sfn|Axworthy|Scafes|Craciunoiu|1995|page=30}}
* {{SEN}}{{sfn|Military Balance 2016|p=464}}
* {{SGP}}<ref name="MF"/>
* {{SUD}}<ref name="MF"/>
* {{RSA}}<ref name="MF"/>
* {{KOR}}<ref name="MF"/>
* {{SRI}}{{sfn|Military Balance 2016|p=289}}
* {{SWE}}<ref name="MF"/>
* {{flaglist|Switzerland}}<ref name="MF"/>
* {{THA}} — M1{{sfn|Military Balance 2016|pp=293–294}}
* {{TLS}}{{citation needed|date=April 2022}}
* {{TUR}} — M1,<ref name="Wiener 1987"/> L/60{{sfn|Military Balance 2016|p=146}}
* {{UAE}}<ref name="MF"/>
* {{UK}} — L/60 built under license
* {{USA}} — L/60 built under license
* {{USSR}}
* {{URU}}<ref name="MF"/>
* {{flag|South Vietnam}}<ref name="MF"/>
* {{flag|Vietnam}}<ref name="MF"/>
* {{VEN}} — M1A1{{sfn|Military Balance 2016|p=417}}
* {{YEM}}<ref name="MF"/>
{{div col end}}

== Wars ==
{{div col|colwidth=33em}}
* [[Second World War]]
* [[First Indochina War]]
* [[Indo-Pakistani wars and conflicts]]
* [[Arab–Israeli conflict]]
* [[Korean War]]
* [[Indonesia–Malaysia confrontation]]
* [[1958 Lebanon crisis]]
* [[Portuguese Colonial War]]
* [[Congo Crisis]]
* [[Eritrean War of Independence]]
* [[Vietnam War]]
* [[Cambodian Civil War]]
* [[Nigerian Civil War]]
* [[Yom Kippur War]]
* [[Ethiopian Civil War]]
* [[South African Border War]]
* [[Falklands War]]
* [[Lebanese Civil War]]
* [[Nicaraguan Revolution]]
* [[Gulf War]]
* [[Yugoslav wars]]
* [[Yemeni Civil War (2015–present)]]
* [[Saudi Arabian-led intervention in Yemen]]
* [[2022 Russian invasion of Ukraine]]
{{div col end}}

== See also ==
* [[Bofors 40 mm Automatic Gun L/70]]
* [[List of anti-aircraft guns]]
* [[List of naval anti-aircraft guns]]
* ''[[The Bofors Gun]]'' – 1968 movie about British airmen in Germany (the gun serves as a [[framing device]])

== Notes ==
{{notelist}}

== References ==
=== Citations ===
{{Reflist|refs=
<ref name=Nord2017-05-16>
{{cite news
 |url         = http://www.45enord.ca/2017/05/marine-royale-canadienne-evalue-nouveau-systeme-darmement-navires-defense-cotiere-nanuk-bofors/
 |title       = La Marine évalue un nouveau système d'armement pour ses navires de défense côtière
 |work        = [[45eNord]]
 |author      = Nicolas le May
 |date        = 2017-05-16
 |language    = fr
 |trans-title = Navy assesses new weapons system for its coastal defense vessels
 |archive-url = https://web.archive.org/web/20181121022011/http://www.45enord.ca/2017/05/marine-royale-canadienne-evalue-nouveau-systeme-darmement-navires-defense-cotiere-nanuk-bofors/
 |archive-date = 21 November 2018
 |access-date  = 2018-11-20
 |url-status   = live
 |quote        = <!-- L’enlèvement des Bofors 40 mm Modèle 60 Mk 5C a donc été approuvé le 31 juillet 2014 et les systèmes ont été enlevés depuis. Les 12 navires de la classe Kingston restent toutefois équipés de deux mitrailleuses lourdes .50cal, a confirmé à 45eNord.ca, le capitaine Rick Donnelly, de la Marine royale canadienne. -->
}}
</ref>
}}

=== Main Sources ===
;Books
{{refbegin}}
* {{cite book |last1=Millican |first1=Charles Bowie |author2=United States War Department |date=September 30, 1942 |title=TM 30-410 &#124; Handbook on the British Army with Supplements on the Royal Air Force and Civilian Defense Organizations 1942 |url=https://archive.org/details/Tm30-410/mode/2up?view=theater |location=[[Washington, D.C.]] |publisher=United States Government Printing Office |oclc=19930228 |ref={{harvid|TM 30-410}} }}
* {{cite book |last=Johnson | first=Melvin M. Jr. |author-link=Melvin Johnson |date=January 1, 1944 |title=Rifles and Machine Guns |url=https://www.amazon.com/Rifles-Machine-Guns-Melvin-Johnson/dp/B000FF4YN4#detailBullets_feature_div |format= Hardcover |publisher=William Morrow and Company |asin=B000FF4YN4 }}
* {{cite book |author1=United States War Department |author2=United States War Office |date=January 17, 1944 |title=TM 9-252 &#124; 40-mm Automatic Gun M1 (AA) and 40-mm Antiaircraft Gun Carriages M2 And M2A1 |url=https://archive.org/details/TM9-252/mode/2up?view=theater |location=[[Washington, D.C.]] |publisher=[[United States Department of War|United States War Department]] |oclc=761390158 |ref={{harvid|TM 9-252}} }}
* {{cite book |last1=Chinn |first1=George M. |year=1955 |title=The Machine Gun, History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons |url=https://www.google.com/books/edition/The_Machine_Gun_History_Evolution_and_De/0QxIAQAAIAAJ?q=bofors+40+mm+%22automatic+gun%22+l/60&kptab=overview&gbpv=0#f=false |publisher=[[Bureau of Ordnance|Ordnance Bureau (Navy Department)]] |location=[[United States]] |access-date=March 21, 2022}}
** {{cite book |last1=Chinn |first1=George M. |year=1955 |title=The Machine Gun, History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons |url=https://books.google.com/books?id=0QxIAQAAIAAJ&dq=bofors+40+mm+%22automatic+gun%22+l%2F60&pg=PA520 |volume=4 |publisher=[[Bureau of Ordnance|Ordnance Bureau (Navy Department)]] |location=[[United States]] |page=520 |access-date=March 21, 2022 |ref={{harvid|BuOrd, Vol. 4, p. 520}} }}
* {{cite book |last=Campbell |first=John |year=1985 |title=Naval Weapons of World War Two |url=https://www.google.com/books/edition/Naval_Weapons_of_World_War_Two/bczawAEACAAJ?hl=en |format=Hardcover |location=[[Annapolis, Maryland]] |publisher=[[Naval Institute Press]] |isbn=0-87021-459-4 }}
* {{cite book |last=Gander |first=Terry |year=1986 |title=The 40mm Bofors Gun |url=https://www.google.com/books/edition/The_40mm_Bofors_Gun/qfWcQAAACAAJ?hl=en |format=Hardcover |edition=2nd |location=[[Wellingborough]], England |publisher=Patrick Stephens |isbn=9780850598407 }}
* {{cite book |last1=Rae |first1=C. J. E. |last2=Harris |first2=A. L. |last3=Bryant |first3=R. K. |year=1987 |title=On target: The Story of the 2/3rd Australian Light Anti-Aircraft Regiment from Formation on 18th July, 1940 Until Disbandment on 14th July, 1943, and the Subsequent Service of 7th Battery, 8th Battery, and 9th Battery, Until the End of World War II |url=https://regimental-books.com.au/product/on-target-the-story-of-2_3rd-australian-light-anti-aircraft-regiment/ |location=[[Melbourne]] |publisher=2/3rd Australian Light Anti-Aircraft Regiment Association |isbn=0731600495 |url-status=live |archive-url=https://web.archive.org/web/20160122033423/http://www.antiaircraft.org.au/about-us/on-target/on-target |archive-date=January 22, 2016 |access-date=August 1, 2025}}
* {{Cite book |last1=Axworthy |first1=Mark |last2=Scafes |first2=Cornel |last3=Craciunoiu |first3=Cristian |date=May 1, 1995 |title=Third Axis, Fourth Ally: Romanian Armed Forces in the European War, 1941–1945 |url=https://www.scribd.com/document/148363237/Third-Axis-Fourth-Ally-Romanian-Armed-Forces-in-the-European-War-1941-45 |format=PDF |location=London |publisher=Arms and Armour |isbn=9781854092670 }}
* {{cite book |last=Bishop |first=Chris |year=2002 |title=The Encyclopedia of Weapons of World War II |url=https://www.google.com/books/edition/The_Encyclopedia_of_Weapons_of_World_War/MuGsf0psjvcC?hl=en |format=Hardcover |location=[[New York (state)|New York]] |publisher=MetroBooks |isbn=9781586637620 |access-date=August 1, 2025}}
* {{Cite book |date=1977 |title=Jane's pocket book of towed artillery|last=Foss|first=Christopher |publisher=Collier |pages=231–233|isbn=0020806000|location=New York|oclc=911907988}}
* {{Cite book |last=Gander |first=Terry |year=2013 |url=https://www.google.com/books/edition/The_Bofors_Gun/-o3PBQAAQBAJ?hl=en&gbpv=0 |title=The Bofors Gun |publisher=Pen and Sword |isbn=978-1-78346-202-5 |language=en}}
** {{cite book |last=Gander |first=Terry |date=April 30, 2013 |title=The Bofors Gun |url=https://books.google.com/books?id=-o3PBQAAQBAJ&q=bofors+L%2F43&pg=PA107 |publisher=Pen and Sword |pages=7, 9 |isbn=9781783462025 |url-status=live |archive-url=https://web.archive.org/web/20181029152324/https://books.google.com/books?id=-o3PBQAAQBAJ&pg=PA107&lpg=PA107&dq=bofors+L%2F43&source=bl&ots=dlLWYaW0dU&sig=-konmcQJRaZIJaGwwiPM34z81Bs&hl=en&sa=X&ved=2ahUKEwjOrb3ByqveAhXuo4sKHT-0Ab0Q6AEwDXoECCgQAQ#v=onepage&q=bofors%20L%2F43&f=false |archive-date=October 29, 2018 |via=[[Wayback Machine]] |ref={{harvid|Bofors 40 mm L/43}} }}
** {{Cite book |last=Gander |first=Terry |date=April 30, 2013 |title=The Bofors Gun |url=https://books.google.com/books?id=-o3PBQAAQBAJ&dq=Japan+captured+a+number+of+Bofors+type+5&pg=PA132 |publisher=Pen and Sword |page=132 |isbn=978-1-78346-202-5 |ref={{harvid|40mm/60 Type 5}} }}
** {{cite book |last=Gander |first=Terry |date=April 30, 2013 |title=The Bofors Gun |url=https://books.google.com/books?id=-o3PBQAAQBAJ&q=l%2F60 |publisher=Pen and Sword |isbn=978-1-78346-202-5 |pages=6, 7, 9, 29, 31, 33 |access-date=March 21, 2022 |ref={{harvid|L/60}} }}
* {{cite book |author=International Institute for Strategic Studies |author-link=International Institute for Strategic Studies|date=February 9, 2016 |title=The Military Balance 2016 |url=https://www.google.com/books/edition/The_Military_Balance_2016/XwV3awEACAAJ?hl=en |volume=116 |format=Paperback |publisher=Routlegde |isbn=9781857438352 |ref={{harvid|Military Balance 2016}} }}

{{refend}}
;Documents and encyclopedias
{{refbegin}}
* {{cite encyclopedia |year=1986 |chapter=16. Défense contre avions 1939–1945 |trans-chapter=16. Defense against aircraft 1939–1945 |title=Bofors de 40 mm |trans-title=Bofors 40 mm |encyclopedia =Encyclopédie des armes : Les forces armées du monde |trans-encyclopedia=Encyclopedia of Weapons: The World's Armed Forces |language=fr |volume=II |publisher=Atlas |pages=1749–1753 |ref={{harvid|Encyclopédie des Armes|1986}} }}
* {{Cite document |title=Principer för benämningar och förkortade beteckningar å marinens artillerimateriel och eldvapen samt motiv för förändringar av modellår m.m. |trans-title=Principles for names and abbreviated designations for the navy's artillery equipment and firearms, as well as reasons for changes in model years, etc. |type=Archival document bundle |language=Swedish |publisher=[[Royal Swedish Naval Materiel Administration]] |location=Sweden |pages=239, 244–256, 261–265, 257–260, 266–267 |ref={{harvid|Swedish archives}} }}
{{refend}}

=== Secondary sources ===
{{refbegin}}
* {{Cite web |title=The Bofors gun that revolutionised air defences |url=https://www.saab.com/newsroom/stories/2020/feburary/the-bofors-gun-that-revolutionised-air-defences |access-date=2022-01-25 |website=saab.com |quote=The big breakthrough came at firing tests in Belgium in 1935 against a British competitor. It was found that the Bofors gun could be moved more than twice as quickly as the competitor’s gun and that it scored three times as many hits when firing on aerial targets. The Belgian officers were amazed. The demonstrations in Belgium took place in the presence of representatives from the French War Ministry. It soon resulted in an order from the French Army, which was quite remarkable. Traditionally, France bought no guns from abroad.|archive-date=25 January 2022 |archive-url=https://web.archive.org/web/20220125142042/https://www.saab.com/newsroom/stories/2020/feburary/the-bofors-gun-that-revolutionised-air-defences |url-status=live |ref={{harvid|40 mm Bofors (saab.com)}} }}
* {{cite web |title=40 ItK/35-39 B Bofors &#124; Finnish Army 1918–1945: Anti-Aircraft Guns Part 2: Medium Guns |url=https://www.jaegerplatoon.net/AA_GUNS2.htm#40ItKBofors |website=jaegerplatoon.net |access-date=December 23, 2024 |ref={{harvid|40 ItK/35-39 B (jaegerplatoon.net)}} }}
* {{cite web |last=DiGiulian |first=Tony |date=June 2, 2025 |orig-date=August 31, 2008 |title=Bofors 40 mm L/60 Model 1936 |url=http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php |website=navweaps.com |access-date=August 1, 2025 |ref={{harvid|40 mm L/60 Model 1936 (NavWeaps)}} }}
** {{cite web |last=DiGiulian |first=Tony |date=June 15, 2016 |orig-date=August 31, 2008 |title=Bofors 40 mm L/60 Model 1936 |url=http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php |website=navweaps.com |url-status=live |archive-url=https://web.archive.org/web/20180216041355/http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.php |archive-date=February 16, 2018 |access-date=February 17, 2018 |ref={{harvid|40 mm L/60 Model 1936 (NavWeaps 2016)}} }}
** {{cite web |last=DiGiulian |first=Tony |date=January 14, 2011 |orig-date=August 31, 2008 |title=Bofors 40 mm/60 (1.57") Model 1936 |url=http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.htm |website=navweaps.com |url-status=live |archive-url=https://web.archive.org/web/20070221160521/http://www.navweaps.com/Weapons/WNUS_4cm-56_mk12.htm |archive-date=February 21, 2007 |access-date=September 24, 2011 |ref={{harvid|40 mm L/60 Model 1936 (NavWeaps 2011)}} }}
* {{cite web |title=AC-130W Stinger II - U.S. Air Force > Fact Sheet Display |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104485/ac-130w-stinger-ii/ |website=U.S. Air Force |publisher=AFSOC Public Affairs |url-status=live |archive-url=https://web.archive.org/web/20180422091432/http://www.af.mil/About-Us/Fact-Sheets/Display/Article/104485/ac-130w-stinger-ii/ |archive-date=April 22, 2018 |access-date=April 18, 2018 |ref={{harvid|AC-130W Stinger II (USAF)}} }}
* {{cite web |title=AC-130J Ghostrider - U.S. Air Force > Fact Sheet Display |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/467756/ac-130j-ghostrider/|website=U.S. Air Force |publisher=AFSOC Public Affairs |url-status=live |archive-url=https://web.archive.org/web/20180428232540/http://www.af.mil/About-Us/Fact-Sheets/Display/Article/467756/ac-130j-ghostrider/|archive-date=April 28, 2018 |access-date=April 18, 2018 |ref={{harvid|AC-130J Ghostrider (USAF)}} }}
* {{cite web |author=<!-- not stated --> |date= |title=Bofors L/60 (40 mm Automatic Gun M1 &#124; QF 40 mm) |url=https://weaponsystems.net/system/1574-Bofors%20L/60 |website=weaponsystems.net |location= |publisher= |access-date=August 1, 2025}}
* {{Cite web |title=Naval Legends: Bofors {{!}} World of Warships (timestamped) |date=March 23, 2017 |url=https://www.youtube.com/watch?v=TqM1PS1YTo0&t=245s |website=[[YouTube]] |publisher=World of Warships Official Channel |url-status=live |archive-url=https://web.archive.org/web/20220125142058/https://www.youtube.com/watch?v=TqM1PS1YTo0&t=245s |archive-date=25 January 2022 |access-date=January 25, 2022 |quote=In March 1932, the official trials of the automatic antiaircraft cannon L60 were completed, and it was put on the market. In 1933, British and American military engineers studied the gun, and were quite impressed - the Swedish system was more effective than the obsolete British Vickers "pom-poms" and had more firepower than the "Chicago pianos" used by the US. |ref={{harvid|Naval Legends (WoWS)}} }}
{{refend}}

== External links ==
{{commons}}
{{refbegin}}
* [https://books.google.com/books?id=1iYDAAAAMBAJ&pg=PP1 1940 ''Popular Science'' cover illustration of twin 40mm Bofors in Swedish service]
* [https://books.google.com/books?id=VCcDAAAAMBAJ&pg=PA73 "New Tools For Army Power", October 1941, ''Popular Science''], pp.&nbsp;73–74 on testing of U.S. version of 40mm Bofors
* [http://www.maritime.org/doc/boforstm252/index.htm 40 mm Automatic Gun M1 (AA) and 40 mm Antiaircraft Gun Carriages M2 and M2A1 TM 9-252]
* [http://maritime.org/doc/bofors40mm/index.htm 40 MM Antiaircraft Gun, OP 820, 1943 : Navy Service Manual] via maritime.org
* [https://www.antiaircraft.org.au/ 2/3rd Australian Light Anti-Aircraft Regiment Association]
{{refend}}

{{Weapons made in Sweden 1914–1945|style=wide}}
{{WWIIBritishCommNavalWeapons}}
{{WWIIUSNavalWeapons}}
{{WWIIBritishCommGuns}}
{{WWIIUSGuns}}

{{DEFAULTSORT:Bofors 40 Mm}}
[[Category:Naval guns of Sweden]]
[[Category:Naval guns of the United States]]
[[Category:Naval guns of the United Kingdom]]
[[Category:World War II anti-aircraft guns]]
[[Category:Naval anti-aircraft guns|40 mm]]
[[Category:World War II naval weapons]]
[[Category:World War II naval weapons of the United Kingdom]]
[[Category:40 mm artillery]]
[[Category:Aircraft artillery]]
[[Category:Vehicle-mounted weapons]]
[[Category:Anti-aircraft guns of Sweden]]
[[Category:Bofors]]
[[Category:Autocannon]]
[[Category:Military equipment introduced in the 1930s]]