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Antitank weapons
used by the Finns in the Winter War
Part I
In Part II
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All
of the AT-guns have in their official Finnish designation the abbreviation
"Pst" included.
"Pst" is an abbreviation from the Finnish term "panssarintorjunta",
which means antitank.
That
"Pst" abbreviation wasn't always used, unless there was another
similar caliber gun in use (e.g. as a field artillery piece
or as an AA-gun), and there was a real chance to mix the
two different weapons with each other.
Thus I use in the text the designation without the "Pst" abbreviation.
e.g. 37 PstK/36 is the same gun as 37
K/36
I
have included the different gun types in the order reflecting the
numbers used,
e.g. the Bofors 37 mm was the most widely used
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Antitank guns
The 37 PstK/36
 
(The gun is attached to the horse drawn front wagon)
This Swedish gun design, made
by Bofors, was at its time one of the most sophisticated
AT-guns in the world. The first prototype was produced in
1932, and the final version in 1934. The weapon was accepted
into the Swedish Army as the "37 mm Pansarvärnskanon m/34".
In time, some improvements were made to the original type,
resulting in the m/38 and m/38F.
In 30 October 1936, the gun was
accepted as the primary AT-weapon for the Finnish Defense
Forces, and the license was bought. In Finland, two factories
were to start the production of the 37 K/36. One was Tampella,
and the other VTT ("Valtion tykkitehdas", "The State
gun factory" in English). Oy Crichton-Vulcan produced
the gun mount and the wheels for the guns. In addition to
Finland and Sweden, many other countries adopted the Bofors
gun, among them Denmark and Poland.
The first order from the Finnish
Army, 156 guns, was placed in 1938, with the two factories.
As there were constant problems in getting the production
started, Finland bought also guns from Sweden, many of which
were of the newer m/38 type.
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Picture source:
"Marskin panssarintuhoojat", p.213
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 The main difference between
the Swedish m/38 and Finnish m/36 (and also the Swedish
m/34) was that the former had an improvement that
wasn't adapted to the Finnish production: a wavelike upper
edge of the gun shield, making it easier to camouflage and
harder to spot (see the picture on the right).
Finnish produced guns didn't have this feature. The gun
shield was 4 - 5 mm thick (weight 46 kg),
but unlike the current German and Soviet designs, the Bofors
gun shields didn't offer any protection from the side.
The guns that were bought or supplied
from Sweden had the targeting scopes attached. For the Finnish
produced guns, the optics had to be bought from abroad,
so for financial reasons, they fought the Winter War relying
on their collimators. This wasn't as bad as it's sounds,
as experience showed that up to medium range of some 400
m, the scope wasn't very superior. In fact, in the dark
hours, the collimator was better as the lens of the scope
easily frosted over in damp air.
(Picture source: "Talvisodan Historia
1", p.169)
At the start
of the war, the Finnish forces had the following number
of 37 mm Bofors guns
| Guns bought from Sweden |
37 K/34 |
48 guns |
| Produced by Tampella |
37 K/36 |
18 guns |
| Produced by VTT |
37 K/36 |
32 guns |
| Total |
|
98 guns |
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Note that most Finnish arms tables
give the figure 112 guns, as the number of 37 mm AT-guns
in Finland on 30 November 1939. The extra 14 guns were
old Rosenberg (37 Jv.K/15) and Obuhov
(37 Jv.K/14) 37 mm infantry guns. They
were counted in the same category as the Bofors guns,
even as though AP-capability of those guns were nearly
nonexistent (at a range of 200 m, the solid AP
projectile penetrated some 10 mm of armor at an 90°
angle).
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By 13 March 1940, the Finnish
troops had received 222 (including the 98 guns at
the start of the war) 37 mm AT-guns. The figure
includes the 17 guns (37 mm K/34) of the
SFK ("Svensk Frivilligkåren", the Swedish Volunteer
Force).
(In Finland, when the production
of 37 mm AT-guns was canceled during the Continuation War,
a total of 355 guns had been produced, 300 by Tampella and
55 by VTT).
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(Picture source:"Marskin
panssarintuhoojat", p.213)
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As the Finnish infantry lacked
AT-rifles, the AT-guns had to be deployed relatively close
to the front-line, resulting in heavy losses. Of the 37
mm AT-guns, 66 were lost in the Winter War for various reasons,
a little over a third of the total number of 37 mm AT-guns.
As the domestic shell production
was also in trouble, the base stock of shells, 32 000, was
bought from Sweden. Note that throughout the Winter War,
Sweden was the main source for shell supply. Even during
the Continuation War some shells had to be bought from abroad.
The gun proved highly effective.
The AP-projectile penetrated the armor of all Soviet tanks
used in the Winter War (with the exception of the
Soviet heavy tank prototypes, which were tested, but in
general, the statement is true).
While the gun was mostly used at
ranges of 400 - 600 meters, the unofficial record was 1
700 meters(other source says 2 000 m), when
a gun of the 7th AT-detachment (Pst.Os.7 in Finnish)
destroyed a T-37 on the ice of Lake Ladoga near Taipale.
Back to Top !
CHARACTERISTICS
OF 37 PstK/36
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Caliber:
Barrel length:
Weight in firing position:
Height of barrel in firing position:
Gun height:
Width:
Traverse:
Elevation:
Max. ROF:
Practical ROF:
Muzzle velocity:
Max. range:
Max. practical range vs. tank:
Max. practical range vs. inf.position:
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37 mm
45 Cal. or 1 736 mm (incl. muzzle brake)
370 kg
625 mm
1 030 mm
1 090 mm
26°
- 10° , + 25°
30 r.p.m.
12 r.p.m.
830 m/s
4.5 km
0.9 km
1.5 km |
The gun had 4 different types of rounds.
- AP-shot ("panssariammus" in Finnish), weighed
1.45 kg , from which the projectile weight was 0.7 kg
- AP-HE shell ("panssarikranaatti" in Finnish)
- Fragmentation shell ("sirpalekranaatti" in Finnish)
- practice shot ("harjoitusammus" in Finnish)
(During the Continuation War, a batch of "phosphorous
incendiary shot" was also produced, "fosforisytytysammus"
in Finnish).
Penetration
AP-projectile (0.7 kg) with the muzzle velocity
was 870 m/s
when the armor plate was at an 60° angle
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| |
300 m |
500 m |
1 000 m |
| Gun manual |
40 mm |
33 mm |
18 mm |
| Test firing in
1943 |
42 mm |
37 mm |
28 mm |
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(Table source:"Marskin panssarintuhoojat",
p.113)
Note: in the test firings, the shot used was an upgraded
AP-shot with a muzzle velocity of 880 m/s
Note that as no data is available
from the armor plate hardness, the performance isn't automatically
comparable to the penetration values of other weapons, especially
if the used source is different.
Back to Top !
The firing
table of the 37 mm Bofors
with the model '34 AP-shell
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| Range |
elevation
(in mils / points) |
flight
duration (sec) |
zenith
during
flight (m) |
effect
of 1 m/sec side wind |
| mils/points |
centimeters |
| 100 |
6 |
0.13 |
0.02 |
0.1 |
2 |
| 200 |
7 |
0.27 |
0.12 |
0.1 |
4 |
| 300 |
8 |
0.42 |
0.25 |
0.1 |
6 |
| 400 |
9 |
0.58 |
0.47 |
0.2 |
8 |
| 500 |
10 |
0.76 |
0.73 |
0.2 |
12 |
| 600 |
11 |
0.95 |
1.1 |
0.2 |
16 |
| 700 |
13 |
1.15 |
1.7 |
0.3 |
20 |
| 800 |
14 |
1.36 |
2.3 |
0.3 |
26 |
| 900 |
16 |
1.59 |
3.2 |
0.4 |
32 |
| 1000 |
18 |
1.83 |
4.3 |
0.4 |
40 |
| 1200 |
22 |
2.35 |
7.1 |
0.5 |
60 |
| 2000 |
47 |
4.83 |
31.0 |
0.9 |
180 |
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Back to Top !
The 45 mm guns
(45 PstK/32, 45 PstK/37 and 45 PstK/38)
In the early 1930s, the Red Army realized its need
of an AT-weapon. At the time, the Soviet Union had working trade
relations and quite close military cooperation with Germany.
The Red Army acquired German 37 mm AT-guns, produced
by Rheinmetal. The Soviet planners were quick to develop their
up-gunned version of the gun, resulting in the "45 mm Protivotankovaja
Puska obr. 1932 g". The sights, the caliber and some manufacturing
solutions were changed, but otherwise the gun was a close copy
of the original German gun.
While the first production models had all wooden wheels,
rubber tires were introduced with the rim of the wheel having
spokes. The m/32 had many unsatisfactory characteristics, and
some of these were sorted out in the newer m/37 model. The most
notable changes were:
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(Picture source: "Talvisodan Historia
4", p.184)
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- The axle of the m/32 had no suspension, reducing
transport speeds (traveling gear). In the m/37,
a new suspension was added, adding suspension cylinders between
the axle and the wheels, increasing the width of the gun by
24 cm. A triggering mechanism was inserted into the hand wheel
of the elevation mechanism. Some other modifications were made
to the traverse mechanism. The loading mechanism was improved
by a new breech block (making it semiautomatic)
thus increasing the rate of fire. Also, the construction of
the wheels was changed.
The next modification to the m/37 was another change
to the suspension. This was made in the following year, and
while the modification left the gun and the characteristics
mostly unchanged, it still was enough change to the logistics
(maintenance & spare parts), that the new
model was designated as m/38.
The first Soviet 45 mm AT-gun was captured by the Finns
in the early days of the war. The gun was immediately noted
to be a good weapon. The construction was somewhat simpler than
in the Finnish guns, but it was still regarded as well suited
for Finnish use. The larger caliber resulted in greater penetration
values than for the 37 mm guns, making the 45 mm AT-gun the
best AT-weapon of the Winter War.
During the Winter War, 125 guns were captured (either
in good order or that could be repaired). I don't have
exact figures of how many were used in combat, but after many
were lost in the last battles of the war, and many were stripped
for spare parts, the exact number on June 1940, were 93 guns
(most were m/32 guns).
All captured guns, that were in good shape were immediately
sent either to the front line troops, or to the AT-gun Training
Center ("Panssarintorjuntatykkikoulutuskeskus" or "Pst.Tyk.Koul.K")
in Hämeenlinna.
Thousands of shells were also captured, and in May
1940, there still were nearly 59 000 rounds in Finnish stores,
and soon after the first order to VTT ("Valtion Tykkitehdas",
"The State Gun Factory" in English) was given, for the
domestic production of 45 mm shells.
(At it's peak, during the "trench war phase"
of the Continuation War, the Finnish Army had 671 guns in use
or in store.)
Back to Top !
CHARACTERISTICS OF 45 PstK/32
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Caliber:
Overall length:
Barrel length:
Weight in firing position:
Height:
Width:
Traverse:
Muzzle velocity:
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45 mm
4 260 mm
46 Cal. or 1 970 mm
425 kg
1 250 mm
1 370 mm
1000 mils
330-760 m/s |
AP-shell 2,4 kg, from which the AP-projectile weight
was 1.43 kg
HE-fragmentation shell 2.8 - 2.9 kg
Canister shot 2.2 kg
Penetration
AP-projectile (1.43 kg),
with the muzzle velocity of 760 m/s,
when the armor was at an 60°
angle
| 100 m |
500 m |
1 000
m |
1 500
m |
2 000
m |
| 43 mm |
35 mm |
28 mm |
23 mm |
19 mm |
(Table source: "Guns vs. Armor"-website,
by D.M.Honner)
Note that as no data is available
from the armor plate hardness, the performance isn't automatically
comparable to the penetration values of other weapons, especially
if the used source is different.
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Back to Top !
The 25 PstK/37
"Canon leger de 25 antichar
SA-L mle 1937"
(Picture source: "Talvisodan Historia 4", p.260)
In the early 1930s, when the majority of tanks were
still light tanks, a new 25 mm AT-gun was designed for the French
Army. This new gun, which was designated as "Canon leger de
25 antichar SA-L mle 1934" became later on the standard AT-gun
of the French Army. It was produced by Hotchkiss.
 A few years later, a lighter
and technically more advanced version was made, the modele 1937.
The characteristics of this newer model were similar to those
of the mle 1934. The mle 1937 was mainly produced by the Puteaux
arsenal.
However, the small caliber, relatively short range and
the small projectile weight (and of course small penetration
value) made these guns nearly obsolete even at the start
of the war.
If glanced at quickly, both guns look very similar,
as both types had two carriage legs and a funnel-shaped flash
suppressor. Distinctive features between the two types were:
- the shield of the m/34 is a bit weird looking two piece shield,
while the m/37 had a single armor shield with vertical hinges
(the shield could be folded during transport)
- the m/34 had metal disc wheels, while m/37 had cartwheel type
steel wheels
- the m/37 has a long recoil spring visible around the barrel,
near the shield
- the m/37 had a funny looking flange plate ("laippalevy"
in Finnish) in the flash suppressor
Finland managed to buy 50 guns (with 25 000
shots) from France, and the first batch of 40 guns left
France on 22 January 1940. The guns arrived via Trondheim in
February. As the fate of the country was being settled, roughly
half of the 40 guns were hurried to the fronts. The 10 remaining
guns never reached Finland in time, the final delay being caused
by Germany's invasion of Norway.
In June 1940, the total number of these guns was 37.
Three guns were lost in the last few weeks of the war.
(Later on, in Fall 1940, Germany offered 200 guns at
a reasonable price from their war booty stores. Finland accepted
and thus after the shipment arrived in December 1940, the number
of 25 mm AT-guns was at its peak 237 guns, from of which
133 were m/34 and 104 were m/37).
The gun was said to be accurate and the sights were
good. The muzzle flash was very small, making the gun hard to
detect. However, the penetration was lousy when compared to
the weight of the gun. The gun was easy to use, and the loading
mechanism was simple, but the other mechanisms were more complex
and not very reliable.
Back to Top !
CHARACTERISTICS OF 25
PstK/37
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Caliber:
Barrel length:
Weight in firing position:
Traverse:
Elevation:
Muzzle velocity:
Max. (theoretical) range:
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25 mm
77 Cal. or 1 810 mm
310 kg
37°
- 10° , + 26°
900 m/s
Max. range: 1800m |
The Finns had 2 different AP-projectiles for this gun.
1) the AP-shot (solid shot)
2) the AP-shot with tracer.
The ballistic and AP-performance of both types were virtually
identical.
Penetration
For the model '34 gun (which had nearly the same performance as
the model '37 gun)
the penetration with the AP-shot (0.32 kg), when the armor plate
is at 60° angle
| 100 m |
500 m |
1 000
m |
| 35 mm |
29 mm |
20 mm |
(Table source: "Guns vs. Armour"-website,
by D.M.Honner)
Note that as no data is available
from the armor plate hardness, the performance isn't automatically
comparable to the penetration values of other weapons, especially
if the used source is different.
E.g. in the fighting north of Ylä-Sommee (some 10 km south
of Viipuri), in late February, a gun team with a 25 mm m/37
AT-gun was attached to the II/JR 15. The team fought a duel
with a BT-7 (it's possible that the tank had problems pinpointing
the gun, as the muzzle flash was hard to detect). Even after
scoring 12 apparently ineffective hits, the tank was still firing
all weapons. Only after the 13th shot found the mark, the tank
suddenly stopped moving and the guns went silent as black smoke
began to come out from the engine compartment of the knocked
out a BT-7. While I don't have information about the range of
the engagement, the AP-performance of the 25 mm AT-gun sounds
questionable as the BT-7 had a maximum armor of 22 mm at an
72° angle (the armor of the model 1937, which had the best armor.
That particular tank could have also been a less armored version).
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Back to Top !
The 20 PstK/40
(The 20 mm "Madsen" automatic cannon)
 
(The gun in the picture is on the wheeled AT-carriage,
note that Finland received those carriages only after the war)
The Danish 20 mm automatic cannon,
produced by the Madsen factory, was one of the most successful
light cannons of the 1930s.
After the war started, the Finnish
Navy and the Air Force immediately expressed their interest
of acquiring Madsen cannons. In early December the Navy asked
that if it could borrow 4 guns, but the request was denied.
The Danish government was very careful in it's open stand on
this conflict, fearing a possible reaction by Germany (very
understandable, regarding Denmark's location). After
this, the situation remained quite unclear for a long time.
In mid-January the Finns heard
that Madsen could sell 28 guns to Finland after all. The requirement
was that, officially, Sweden should be the buyer. The only obstacle
now present was the information that Madsen couldn't provide
any ammunition for the guns. In February, a message arrived
from London that a Kynoch-corporation could produce 20 mm Madsen
ammunition, and so, at last a deal could be made.
28 guns were ordered, and from
these 19 arrived that same month (the rest arrived during
the following summer). Finnish industrial installations
ordered 10 guns, and through their channels some guns were given
as a gift. The Danish voluntary unit brought 10 guns with them.
More guns were ordered, and while in its peak (September
1943) there were 211 guns in Finland, as far as I know,
the number of 20 mm Madsen that arrived to Finland during the
war was some 30 guns.
This air-cooled gun could fire
both single shots, or automatic fire. The gun was supplied with
4 different mounts. A naval mount, a 2-wheeled towed carriage,
a general-purpose tripod and about 20 low silhouette wheeled
AT-carriages. Note that the wheeled AT-carriages arrived only
after the war.
As the need for AT weapons was
so overwhelming, some guns were attached to sledges, and used
as AT-weapons. The result wasn't a very good or efficient AT-weapon,
but it was better than nothing.
Back to Top !
CHARACTERISTICS OF 20 PstK/40
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Caliber:
Barrel length:
Overall length:
Weight in firing position:
Gun weight:
Cyclic rate:
Feed device:
Muzzle velocity:
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20.1 mm
1 200 mm
2 500 mm
160 kg
app. 53 kg
350 r.p.m.
15-round drum
730-890 m/s |
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Penetration
During the Finnish firing tests, that were
made during the war, the following penetration was recorded by the
"20 psav-vj" AP-shot ("-vj" means tracer) with the
muzzle velocity of 775 m/s. The armor plate was at an 70° angle.
| 100 m |
200 m |
300 m |
400 m |
500 m |
600 m |
800 m |
1 000 m |
1 500 m |
| 25 mm |
22 mm |
20 mm |
18 mm |
16 mm |
15 mm |
11 mm |
8 mm |
5 mm |
Data was kindly provided
by Esa Muikku
Note that as no data is available
from the armor plate hardness, the performance isn't automatically
comparable to the penetration values of other weapons, especially
if the used source is different.
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Back to "Weapons
used in Winter War" -page
Back to "Finnish
AT-weapons"-page
Go to Part II
Proofread by : Dale Milton, Solomons
Maryland USA
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