The Famous 40mm Bofors Family

[Tzoli]

Those who are into a bit of military either army (artillery) or naval (AA) are sure to know about the famous Swedish 40mm Bofors Guns.
What I wish to know are the different models, their name and introduction/design dates, and if possible photos or drawings of them.
Based on this site (as well Wiki):
http://www.navweaps.com/Weapons/WNSweden_Main.htm
I know this Models:

Swedish:
(L/60 calibre ones)
Bofors 40mm Model 1930 (1930) (Prototype)
Bofors 40mm Model 1936 (1936)
(L/70 calibre ones)
Bofors 40mm Model 1948 (1948)
Bofors 40mm Model 1958 (1958)
Bofors 40mm Mark 3 (?)
Bofors 40mm Mark 4 (?)
Bofors 40mm SAK-40-315 (?)
Bofors 40mm SAK-40-350 (?)
Bofors 40mm SAK-40-520 (?)
Bofors 40mm SAK-40-600 (?)
Bofors 40mm Sea Trinity (1984)

Australian variants:
(L/60 calibre ones)
40mm 40/60AN (1979?)

British variants:
(L/53.3 calibre ones)
40mm QF Mark I (1937)
40mm QF Mark III (1940)
40mm QF Mark IV (1942)
40mm QF Mark V (1942)
40mm QF Mark VI (1942)
40mm QF Mark VII (1945)
40mm QF Mark VIII (?)
40mm QF Mark IX (?)
40mm QF Mark X (?)
40mm QF Mark XI (?)
40mm QF Mark XII (1943)
40mm QF Mark NI (?)
40mm QF Mark NI/I (?)
40mm QF Mark 3 (?)
40mm QF Mark 5 (?)
40mm QF Mark 5C Boffin (?)
40mm QF Mark 8 (?)
40mm QF Mark 9 (?)

Finnish:
(L/60 calibre ones)
40mm ItK/38 (1938)

German:
(L/56 calibre ones)
4cm Flak 28 (1943)

Hungarian:
(L/60 calibre ones)
40mm 36M AA Gun (1936)

Italian:
(L/70 calibre ones)
Oto Breda 40mm Compact (1960)
Oto Breda 40mm Fast Forty (1965)
Oto Breda 40mm Type 64 (?)
Oto Breda 40mm Type 106 (1969)
Oto Breda 40mm Type 107 (?)
Oto Breda 40mm Type 520R (?)
Oto Breda 40mm Type 564 (1971)

Japanese:
(L/60 calibre ones)
40mm Type 5 (1945)

Spanish:
(L/70 calibre ones)
40mm Bofors-Bazán (?)

US variants:
(L/53 calibre ones)
40mm Mark 1 (1941)
40mm Mark 2 (1941)
40mm Mark 3 (1944)
40mm Mark 4 (1944)
40mm Mark M1 (1944)


So can you help me gather more variants if exists and their design dates?

 

[tiikki]

From Finnish military guide for 40 Itk Bofors dated 1979 and from "antiaircraft yearbooks" published by AA officers club.
Itk = IlmaTorjuntaKanuuna (Ilma = air, Torjunta ~ anti, Kanuuna = cannon)
All these are L/60 models

40 ItK 35
Original Bofors with model 35 Bofors sights/calculator
40 ItK 36
Bofors with model 36 Goerz sights/calculator + electric/hydraulic system
40 ItK 36 59
40 ItK modernized by Italian m/P 26 Galileo calculator and motors (year 1959)
40 ItK 38
Bofors made in Finland by VTT (Valtion TykkiTehdas, State Cannon Factory), sights/calculator model 38 Bofors
40 ItK 38 S
Bofors made in Germany (Saksa in Finnish), sights/calculator model 38 S Bofors.
Also Polish Bofors were given this type number as they were extremely similar to these
40 ItK 38 U
Hungarian (Unkari) Bofors, sights/calculator model 38 U Bofors
40 ItK 39
English Bofors with model 38 Bofors sights/calculator

All of these should have following characteristics:
Barrel length 2250mm, of which 1933.6 mm with rifles.

model 35 elevation limits: -10deg to 90deg
model 38 S limits: -1deg to 90deg
others: -6deg to 90deg

Also:
40 ItK 36BK2 (Bofors Kiinteä 2, Fixed 2 barrels)
Naval version with central command system
40 ItK 37BK
Naval single barrel, with model 35 sights/calculator
40 ItK 38BK
Fixed installation, with model 35 sights/calculator


From "Cannons of the Independent Finnish Navy 1918-2004"
Previously mentioned naval versions
40 60 ItK/35-39 B
Army version bolted on a ship
40 60 ItK/35-39 BK
As above, I'm assuming K = kiinteä (fixed)

L70 versions:

40 70 58 LT (Finnish type name) / SAK 40/70 FI58 (Bofors type name)
Bought year 58, naval version with central direction, possibility for multiple cannons at the same time
40 70 66 LT / SAK 40/70 FI58B
Ordered 64, small changes to the central direction system, same cannon.

40 70 78 LT / SAK 40/L70 A
Bought year 78, naval, similar direction system as in 58B, increased rate fire.

40 70 89 LT / SAK 40/L70 E
Bought year 89, cannon based on "Trinity" design. 99+2 ammunition clip size

SAK 40/L70 EL
Digitized electric direction system, single prototype bought to Finland. 99+2 ammunition clip size.

 

[Tzoli]

Thanks, do the later ones have dates for them?
I've already stated one SAK-40 version the 350 but I don't know it's design/introduction date

 

[tiikki]

Found another set of Bofors from the Navy book.

40 60 M5 2LT / 40/60 Mk5 (British)
British twin Mk5 guns installed on training ship Matti Kurki (old British Bay-class frigate, bought by Finland 1962), liquid cooled, with electric motor, first installed on 1945 in Hunt class destroyer

40 60 M8 / 40/60 Mk8
British guns with air cooling, bought 1957.

40 60 M9 / 40/60 Mk9
British guns, installed in Matti Kurki, electric motor, can be used with central direction, limited traverse


For the SAK cannons only date information is the year of purchase. The last one was a project to update model 58-guns, but it failed and the gun was not taken into service and Finnish Navy resigned from the deal 2001.

 

[tiikki]

I just found this from Swedish forum http://forum.soldf.com/topic/49429-bae-to-test-lighter-40mm-naval-gun-on-swedish-patrol-boat/

Benämningar på 40 mm apjäs m/1948:

Bofors beteckning Innebörd SAK SkeppsAutomatKanon S48, S52, S56 etc S = Sverige, 48, 52, 56 etc. anger leveransår till flottan SAK 40 L/70 A eller SAK 40 L/70-350 A = Fjärr- och närstyrd SAK 40 L/70 E eller SAK 40 L/70-600 När- och fjärrstyrd, eldhast 330 skott/min, "Balderiserad" och med 99-skottsmagasin finns ej i svenska försvaret SAK 40 L/70 F eller TRINITY Pjäsen har plastkupol med 57 Mk2-design och förekommer bl.a. på Brasilianska flottans Niteroi-klass fregatter. Pjäsen har ej anskaffats till svenska fartyg 40 mm apjäs m/48 olika varianter benämns av försvarsmakten och FMV med bokstavskombinationer: A eller D Bofors beteckning SAK 40 S48, S52, S51 Huvudspänning 110 VDC B Bofors beteckning SAK 40 S48 Huvudspänning 220 VDC C, E, F eller H Bofors beteckningar SAK 40 S56B, SAK 40 S53, SAK 40 S54 och SAK 40 S54B Huvudspänning 440 VAC 60 Hz G eller K Bofors beteckning SAK 40 S 55 Huvudspänning 380 VAC 50 Hz EL Elektriskt riktsystem (Endast en prototyppjäs framtagen) Efterföljande bokstäver: T transistoriserat riktsystem P pjäsen är försedd med plastkupol SV sidvinkelmottagare vid HR-platsen GS pjäsen är gyrostabiliserad R pjäsen är försedd med raketställ

- Eldhastigheten för 40 Mk2 är 240 skott/min

- 40 Mk2 kan inte programmera 3P-ammunition. Dock kan 3P-ammunition skjutas med 40 Mk2 men då enbart med funktionen zonrör
Med vänlig hälsningJessica FranzénFMV – Försvarets materielverk

For what I could understand and with Google Translate:

SAK = Ship Automatic Cannon
SAK 40 L/70 A = SAK 40 L/70-350 A, cannon with remote and local control
SAK 40 L/70 L = SAK 40 L/70-600 E, cannon with higher ROF and 99 ammunition clip

Then there is stuff giving information about gun marks in Swedish military (if I understood correctly not related to Bofors own markings) A or D marks can be from years 48, 52, or 51 with electric system being 110 VDC, B is from 48 with 220 VDC. C,E,F,H can be 56, 53, or 54 models with 440 VAC 60Hz, G and K are from year 55 with 380 VAC 50 Hz system.

Opinion from native Swedish speaker would be nice

 

[Tzoli]

Thx I've added the Finnish, Hungarian (Why did I forget this?) and the SAK-40-600 Swedish one, the others what I've read in your post are only bought guns in Finnish service. still no dates for them

 

[Jemiba]

For the post war German versions :

- Flak 40mm L70: Used by the airforce since 1958 and by the army since 1960
Some were given to the navy and modified by Breda, without a change in the designation
- The suffixes "MEL" (Marine Einzellafette) or "MDL" (Marine Doppellafette) designates ship
board single and twin mounts.

 

[Tzoli]

But are those manufactured by Germany (West Germany) or just bought from Sweden?
I need info on built ones not bought ones.

The ?'s in brackets show I don't know their introduction/design dates

 

[tiikki]

Well, the SAK 40/L70 EL was left on the prototype status on 2001 when Finnish Navy pulled out of the order. It was supposed to be a modernization of model 58 cannons but practically nothing from an old cannon was usable. Finnish Navy ended up having a single modernized weapon without any support.

It looks like that there was SAK 40 N67 sold to Norway.
http://www.intercontrol.no/Oppgradering-Marine-01.pdf


Maybe contacting BAE Systems and Land Armaments (current owners of Bofors) might result something? http://www.baesystems.com/page/contact_us

 

[Tzoli]

You think they would give me data about their most famous product which is still in development and upgrading since it's introduction in 1936?

 

[tiikki]

You think they would give me data about their most famous product which is still in development and upgrading since it's introduction in 1936?

We shall see. I sent an email to the head of marketing / communications in Sweden.

 

[JFC Fuller]

I have always been curious about the Japanese Type 5 variant but have never managed to find any details about either it or its proposed mountings..?

All available commentary on the Japanese work on the 40mm bofors seems to be derived directly from the US post-war intelligence report into Japanese light and medium AA weapons which is available here: http://www.fischer-tropsch.org/primary_documents/gvt_reports/USNAVY/USNTMJ Reports/USNTMJ-200F-0524-0618 Report O-47 N-2.pdf

I find it astonishing that the Japanese did so little to develop a replacement for their 25mm AA gun when they were both aware of its deficiencies and were comparatively innovative in developing heavier aircraft cannon.

 

[Tzoli]

I have always been curious about the Japanese Type 5 variant but have never managed to find any details about either it or its proposed mountings..?

From the Naval Weapon site:

[font=arial,helvetica]Notes on Japanese Weapons and Mountings[/font] [font=arial,helvetica]The Type 5 (Model 1945) originated from the capture of a British Bofors air-cooled gun in a single hand-worked mounting at Singapore in 1942. A Japanese copy underwent prototype firing trials in 1943 at the Torigasaki range of the Yokosuka Naval Arsenal and limited production began in that year, but the gun was never perfected and it did not go into general service use. However, some 5 to 7 weapons a month were being produced in late 1944, apparently for service evaluation purposes. The main alteration from the British Bofors design was to increase the bore length to 94.49 in (2.400 m) - 60 calibers - and to add Rhienmetall-style flash suppressors, which proved unsatisfactory. Production was at the Yokosuka Naval Arsenal and at the Hitachi Manufacturing Company. Used only in manually-worked single mountings, which had an elevation range of -10 / +95 degrees and a weight of 1,870 lbs. (850 kg). Recoil was 8.5" (21.6 cm). Major problems found by the USN after the surrender were that poor manufacturing caused improper seating of rounds and jamming of parts, and that the star wheels and extractors were frequently mismated.[/font]
[font=arial,helvetica]Nomenclature Note: Although the Japanese designation is normally described as the Type 5 (Model 1945), "US Naval Technical Mission to Japan report O-47(N)-2" at one point (page 16) describes the Mechanism designation as "Type 5 (1943)," which cannot be correct as the numbers do not match. This error may imply that the designation would actually be "Type 3" (Model 1943) which would seem to be more in keeping with the actual Japanese design date of 1943. However, it should be noted that the Japanese Model number system, normally based upon the year the breech design was started, became very chaotic towards the end of World War II, with new weapons having Type years that had no relationship to the actual year that the breech design was started. So, this weapon may indeed have been designated as Type 5.[/font]

 

[Tzoli]

I again need help about Bofors guns. This time I'm making drawings about the proposed British Guided Missile Cruisers of 50's, the GW series of designs. And for them I could use drawings or photos of the 40mm 70calibre twin mounts. Can anybody help me?

 

[Tzoli]

Another request for help, this time I could use drawings for the British 40mm STAAG mount preferably the Mark 2 variant both top and side views, and the Mark VII single mounting.

 

[Artie Bob]

Just nostalgia, my memories of being a first loader on a 40mm quad mount during my first USN training cruise on the USS Wisconsin (BB-64) in 1955. It was a lot of fun during our live fire training , shooting at aircraft towed sleeves. In later years, I was a first loader on a 3"/50 twin mount. Not nearly as much fun, strong muzzle blast, more noise, a single round that was much heavier than the 40mm clip, and a very awkward, crowded loading position.

Best regards,

ArtieBob

 

[Forest Green]

View: https://www.youtube.com/watch?v=i1WJb2UyVXs