20mm AT-weapon at Winter War

[Juha Tompuri]

Finnish sources seem to lack accurate information when it comes to weapons that SFK brougth with it.

Yes, and, Isn't this the crucial point here! And at moment we must find the most beliveble facts, or how to put it, that it was Swedish bought 20 mm Madsens with 15 round mags that the text is about
So. We need Swedish sources about the weapon in use, in Sweden and in SFK, to confirm the statement in the original text...

Wonder what was the fate of the SFK Madsens, were they left at Finland or did they take them to Sweden.
The 15 round magazine mentioned doesn't seem to support the first option.

Regards, Juha

[Philip S. Walker]

BTW, unlike Philip S. Walker claimed, 20-mm Madsen wasn't particularly good 20-mm automatic cannon. German 20-mm guns and Finnish 20 ItK/40 VKT were all superior designs compared to it.

Of course. I should have guessed. Sorry.

When will I ever learn?

(PS. Jagala, there's a PM waiting for you, and a friendly one, too.)

Regards, Vely

[Vaeltaja]

BTW, unlike Philip S. Walker claimed, 20-mm Madsen wasn't particularly good 20-mm automatic cannon. German 20-mm guns and Finnish 20 ItK/40 VKT were all superior designs compared to it.

Of course. I should have guessed. Sorry.

Well i'm not sure of this refers to all of the Madsen 20-mm guns. That is the early model Madsens (bought 1930 or so) were problematic and rather bad guns but then again so were the Lahti 20-mm guns used on the rest of the VMV boats. I'm not aware that the later model Madsens would have had equal amount of reliability issues, in fact AFAIK the later model Madsens were used to replace both the early model Madsens and Lahti guns. Barrel explosions at Madsens during the war were not really down to weapons bad quality (AFAIK) but more to the fact that they were fired at sustained rate far beyond design limits (barrel overheating).

Real problem with Madsen (something which Finnish Navy Ship Design Bureau/Finnish Navy HQ refused to admit until the end of the war) was that it was insufficient. For the first part of the war Soviets used level bombers against ships against which Madsen's (like other 20-mm guns as well) lack of range was problematic, later on Soviets switched over to using armored/sturdy A-20s and IL-2 ground attack planes against which Madsens (again like other 20-mm guns) proved to be more or less useless. Neither did it really work that well against surface targets, (somewhat) stabilized 40-mm Bofors was in every way superior to 'harness aimed' 20-mm Madsens (again same applies to all 20-mm guns) and when Soviets introduced (lightly) armored patrol boats Madsens hitting power from long range was not sufficient (close up it worked fine, like at Someri). But as said most if not all the points above regarding Madsens apply to all 20-mm AA guns in naval use.

[Juha Tompuri]

BTW, unlike Philip S. Walker claimed, 20-mm Madsen wasn't particularly good 20-mm automatic cannon. German 20-mm guns and Finnish 20 ItK/40 VKT were all superior designs compared to it.

Of course. I should have guessed. Sorry.

Well i'm not sure of this refers to all of the Madsen 20-mm guns. That is the early model Madsens (bought 1930 or so) were problematic and rather bad guns

Yes.

but then again so were the Lahti 20-mm guns used on the rest of the VMV boats.

I do not know of the L-34 problems.
And at least I don't know of any cases the L-34's been fatal to the own gun crew, as had been with Madsens several times.
Could you enlighten about the your mentioned problem types?

I'm not aware that the later model Madsens would have had equal amount of reliability issues, in fact AFAIK the later model Madsens were used to replace both the early model Madsens and Lahti guns. Barrel explosions at Madsens during the war were not really down to weapons bad quality (AFAIK) but more to the fact that they were fired at sustained rate far beyond design limits (barrel overheating).

Also the "mid" model Madsens (Finnish designations 20 ItK 36 and 20 ItK 39) suffered from the barrel explosions.
The reason of the Madsen barrel explosions was the faulty design, it fired from closed bolt.
Unlike for example the L-34.
The Madsen problem was fixed (by the manufacturer) at the later bought models, and by Finnish modifications at the earlier bought guns.

Regards, Juha

[JTV]

since there is no mentioning what so ever about them ever seeing ground use.

From Pitkänen&Simpanen book:

Notice it's Tampella-made version of L-34. Valtion Kivääritehdas (State Rifle Factory, VKT) was the "main" manufacturer of L-34 (several prototypes and the dozen series II guns made for Coastal Guard). Tampella made only two L-34 automatic cannons, which were both used as anti-aircraft defense of the factory during Winter War and Continuation War (the gun crews were Civil Guard members belonging to factory workers). Hence the two guns never left the factory.

Jarkko

[Juha Tompuri]

since there is no mentioning what so ever about them ever seeing ground use.

From Pitkänen&Simpanen book:

Notice it's Tampella-made version of L-34.

I knew it, and left the photo caption for everyone else see the manufacturer too.

Hence the two guns never left the factory.

I think that the main point for the possibility I mentioned was that the ground mount existed, and there were L-34's availlable.


Regards, Juha

[JTV]

Barrel explosions at Madsens during the war were not really down to weapons bad quality (AFAIK) but more to the fact that they were fired at sustained rate far beyond design limits (barrel overheating).

To be exact the biggest problem was related to structural design of Madsen, which combined tendency to overheat with design that fired from the closed breech (or closed bolt). While I know this is technical jargon, it simply refers to fact that when shooting is paused:
1. With closed breech/bolt: The bolt remains (forward in) closed position with live cartridge in cartridge chamber.
2. With open breech/bolt: The bolt remains (rear in) open position and no live cartridge in cartridge chamber.
Open breech/bolt design usually also allows the weapon to cool down much faster (because of which is very popular in automatic weapons). With closed breech/bolt designs there is certain tendency for the live cartridge in chamber to go off because of heat eminating to it from barrel. This problem wasn't limited to only early Madsen cannons.

Real problem with Madsen (something which Finnish Navy Ship Design Bureau/Finnish Navy HQ refused to admit until the end of the war) was that it was insufficient.

You are absolutely correct in this being a serious problem, however in somewhat different manner - practical usefullness in existing/developing environment vs. technical problems. IMO the matter was rather complicated, since at the time there were not much of real options available caliber range in between 20-mm and 40-mm. German 37-mm guns were about as heavy as 40-mm Bofors, but ballistics-wise inferior, so they were not a useful alternative. Soviet 37-mm were not captured in such numbers that they could have been introduced to own use and they weight also about the same as 40-mm Bofors. IL-2 was difficult customer for 20-mm, while 40-mm Bofors was notably larger and heavier gun, which made its use problematic in small boats. Hence when there was no real better option available, their stand is rather understandable and the matter related to use of 20-mm anti-aircraft guns in general - there was need for slightly larger (and heavier) anti-aircraft gun that would have fired more potent ammunition, but there were no such gun available.

As for Winter War, which the period under discussion - 20-mm was still quite satisfactory at that time for the purpose that it was used for - anti-aircraft gun against low-flying aircraft.

Jarkko

[Vaeltaja]

And at least I don't know of any cases the L-34's been fatal to the own gun crew, as had been with Madsens several times.
Could you enlighten about the your mentioned problem types?

Well.. Not specifically. In 'Suomen Laivasto 1918-1968 II' in 'Liite I' there is a mention "Veneiden vakinaisena aseena merivartioinnissa oli 1/20 L-S konetykki, joka oli epäluotettava ja vailla ammuksia..." (Standard armament for the boats during coast guard duty was 1/20 L-S automatic gun which was unreliable and had no ammo available). In 'Suomen Laivasto 1918-1968 I' the ammo status is discussed in slightly more detail and it reveals that there were no AA ammo (presumably API-T or equivalent type ammo) available for the 20/60-L guns (at least during Winter War) - though several thousand shells had been promised for the spring (not revealed if they were delivered).

Hence when there was no real better option available, their stand is rather understandable and the matter related to use of 20-mm anti-aircraft guns in general - there was need for slightly larger (and heavier) anti-aircraft gun that would have fired more potent ammunition, but there were no such gun available.

As for Winter War, which the period under discussion - 20-mm was still quite satisfactory at that time for the purpose that it was used for - anti-aircraft gun against low-flying aircraft.

All true but there were examples of Navy's apparent fascination with the Madsen or 20 mm guns. For example Turunmaa type gunboats had no 40 mm AA even until the end of the war. Same goes with auxiliary gunboats Aunus and Viena of which other had 1 x 40 mm and second had none of those. The Navy's attachment to the 20 mm guns is criticized in books as well (in addition to me).

[Juha Tompuri]

And at least I don't know of any cases the L-34's been fatal to the own gun crew, as had been with Madsens several times.
Could you enlighten about the your mentioned problem types?

Well.. Not specifically. In 'Suomen Laivasto 1918-1968 II' in 'Liite I' there is a mention "Veneiden vakinaisena aseena merivartioinnissa oli 1/20 L-S konetykki, joka oli epäluotettava ja vailla ammuksia..." (Standard armament for the boats during coast guard duty was 1/20 L-S automatic gun which was unreliable and had no ammo available).

Interesting that AFAIK Pitkänen&Simpanen nor Vesa Toivonen at his Tampellasta Patriaan which both quite detailled deal with the L-34's, do not mention of any kind of functional problems.
The claim that there was no ammo is hardly correct. At least if it means the here relevant war-time situation.
The different ammo type and small number of the L-34's itself sure was a logistical problem.

Regards, Juha

[Vaeltaja]

As i posted it seems to have been reference to the AA ammo (ie. probably referring to tracers).

[John T]

Thanks, really nice info. Finnish sources seem to lack accurate information when it comes to weapons that SFK brougth with it. Universal mount might likely be the same as multipurpose-mount (tripod with removable wheels, photo shown in my last post)? Hmm... kompanilavett - I have vague recollection of seeing old Madsen cannon manual that used that term, but I'm no longer 100% certain which mount version it was? Do you have any info?

Jarkko

I assume that kompanilavett is what the Danes called "feltlavet"
http://www.chakoten.dk/cgi-bin/fm.cgi?lang=dk&n=640
But the only factual for that is that they where organized in the anti tank plt.
Cheers
/John

[John T]

Finnish sources seem to lack accurate information when it comes to weapons that SFK brougth with it.

Yes, and, Isn't this the crucial point here! And at moment we must find the most beliveble facts, or how to put it, that it was Swedish bought 20 mm Madsens with 15 round mags that the text is about
So. We need Swedish sources about the weapon in use, in Sweden and in SFK, to confirm the statement in the original text...

Wonder what was the fate of the SFK Madsens, were they left at Finland or did they take them to Sweden.
The 15 round magazine mentioned doesn't seem to support the first option.

Regards, Juha

They stayed in Finland, basically anything that got into Finland stayed there, as the explicit order where phrased something like "The least we (sweden) could to to leave our gear to the Finns. - Not the exact wording but something with that meaning where in the Corps-orders after the armistice.
And there is no references(as I have found) to Madsens in Swedish service.

cheers
/John

[Philip S. Walker]

And there is no references(as I have found) to Madsens in Swedish service.

Among countries using 20-mm Madsen gun before or during WW2 were Denmark, Sweden, Finland, Norway, Estonia, Czechoslovakia, Poland, Belgium, France and Germany. Source: http://www.jaegerplatoon.net/AT_GUNS1.htm

Since the Swedes introduced a Bofors 20 mm gun in 1940, I assumed that the Madsen's they also had (according to the above source) would be from before that.

I assume that kompanilavett is what the Danes called "feltlavet"

I don't know what "kompanilavett" is exactly, so I can't reply, but I think the pictures show what a "feltlavet" is. "Field gun carriage" might cover it in English. In Denmark this gun was also used by motorised infantry and mounted where the sidecar would otherwise be on a Nimbus motorcycle, hence the need to distinguish.

The Bofors 20 mm was used by Danforce, the Danish commandoes-in-exile who were trained in Sweden during the war. There are some picture and some info about it here: http://www.chakoten.dk/cgi-bin/fm.cgi?n=546

Finally a bit of information about Madsen light machine-guns bought by Finland, Spain and Estonia: http://www.chakoten.dk/cgi-bin/fm.cgi?n=1093

Regards, Vely

[JTV]

They stayed in Finland, basically anything that got into Finland stayed there, as the explicit order where phrased something like "The least we (sweden) could to to leave our gear to the Finns. - Not the exact wording but something with that meaning where in the Corps-orders after the armistice.

That was what happened when the Winter War, but the situation didn't stay like that very long before thing started changing. After Germany invaded Denmark and Norway in 1940, Sweden asked part of the weapons delivered to Finland to be returned. Among these returned weapons were some 37-mm Bofors antitank-guns that had arrived to Finland with SFK. Later around 1943 - 1944 also 6.5-mm machineguns /1914, which had also originally arrived to Finland with SFK, were sold back to Sweden. I'm also not 100% certain about the 24 light field guns 75 K/02, which were returned to Sweden after Winter War - they may have included some of the 12 guns which belonged to equipment that arrived with SFK.

What ever the 20-mm guns may have been, IMO it would have been quite possible for them to have been returned to Sweden already in 1940. It's known that eight 40-mm Bofors aa-guns that had belonged to SFK were transferred to Finnish Armed Forces after the war (*). However SFK also had some (four?) 75-mm Bofors anti-aircraft guns with it - and apparently these didn't stay in Finland very long.

(*) Itsenäisen Suomen Ilmatorjuntatykit 1917 - 2000 by Vehviläinen, Lappi and Palokangas, page 100.

I tried searching photos of the Madsen manual (for more info about "kompanilavett") from my computers, but apparently I didn't photograph it.

Jarkko

[John T]

They stayed in Finland, basically anything that got into Finland stayed there, as the explicit order where phrased something like "The least we (sweden) could to to leave our gear to the Finns. - Not the exact wording but something with that meaning where in the Corps-orders after the armistice.

That was what happened when the Winter War, but the situation didn't stay like that very long before thing started changing. After Germany invaded Denmark and Norway in 1940, Sweden asked part of the weapons delivered to Finland to be returned.

Yes, My Bad. But note that SFK them self intended to leave all materiel in Finland. It was trough Swedish diplomatic channels the question where raised for a return of arms to Sweden.
Your right but only standard issue for Swedish armed forces where of interest.

Among these returned weapons were some 37-mm Bofors antitank-guns that had arrived to Finland with SFK.

Yes, but 13 of the returned guns where with Finnish shields, and got their own designation in Sweden
"37mm pvkan m/38-F" (for Finland) So I have assumed these where built in Finland.
But I do not have barrelnumbers of those.

Later around 1943 - 1944 also 6.5-mm machineguns /1914, which had also originally arrived to Finland with SFK, were sold back to Sweden.

Yes, got a list of those, with the 15cm guns returned too, but those where sold back

I'm also not 100% certain about the 24 light field guns 75 K/02, which were returned to Sweden after Winter War - they may have included some of the 12 guns which belonged to equipment that arrived with SFK.

Do you got barrel numbers of those ?
And attached document gives then as 24 from Finnish army use and 12 from SFK.

Remember a long time ago we could not agree on whether it was 60 or 72 Swedish m/02 guns in Finland.
Doesn't this makes the math fit from both sides - Finland never counted the SFK guns as Finnish while the Swedes counted them as given to Finland?

What ever the 20-mm guns may have been, IMO it would have been quite possible for them to have been returned to Sweden already in 1940.

I never seen any reference of Swedish Madsens operational so I do still doubt it.

However SFK also had some (four?) 75-mm Bofors anti-aircraft guns with it - and apparently these didn't stay in Finland very long.

Yes, dug up this one:

Cheers
/John