ANTITANK GUNS PART 1:

20 mm - 37 mm Guns

 

20 PstK/40 Madsen

(20 mm antitank gun M/40 Madsen)

PICTURE: 20 mm Madsen automatic gun with antitank mount. This gun has 10-round drum magazine attached to it. (Photo taken in Jalkaväkimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (119 KB).

Calibre:

20 mm x 120 Madsen

Length:

250 cm

Barrel length:

120 cm aka L/60

Weight in action:

160 kg (with AT-mount used) (*)

Rate of fire:

350/min (theoretical) / 200 - 250/min (practical)

Muzzle velocity:

Theoretical: 730 - 890 m/sec

in reality: 690 - 780 m/sec

Magazine:

10 (drum), (15 (box), 40 (drum) and 60 (drum) (**)

Width:

110 cm

Height:

80 cm

Country of origin:

Denmark

Ammunition types:

AP-T, APHE, HE-T, HE

(*) Weight of just the automatic cannon without gun mount of any sort about 53 kg.

(**) Photo evidence suggests that 10-round drum magazine was likely the typical magazine type used with 20 PstK/40, but other magazine types made for 20-mm Madsen fit to it as well. 40-round drum was the original magazine for anti-aircaft guns. Madsen factory delivered also later introduced 60-round drums to Finland with model 1940 variation of the Madsen anti-aircraft gun during World War and 15-round box magazines were likely also used at least during Winter War. All of these magazines were removable.

Armour Penetration:

- Results of Finnish test firing in 1941:

- "Guns vs Armour website" by D.M. Honner (likely 158-gram AP-T projectile "20 psav - Vj5", 775 m/sec, 5-second tracer):

- Finnish live fire testing year 1943 ("20 psav-Vj" AP-T, 775 m/sec):

Finnish use: 20-mm Madsen automatic guns were mostly used as anti-aircraft guns in Finland. During Winter War few used as antitank-guns with improvised sledge mounts. Later during early part of Continuation War small number with antitank / ground support gun carriages (one-axle wheeled mount) guns were used as antitank-guns. By March of 1942 all of these guns of antitank-gun version had been transferred to coastal troops.

This automatic cannon was developed in Madsen factory (Dansk Rekylriffel Syndikat A/S / Dansk Industri Synkikat A/S Compagnie Madsen) in Denmark. It was introduced in year 1926 and become commercial success in 1930's. It was select-fire recoil action automatic cannon capable both to semiautomatic and full automatic fire. Weapon had several mount options, from these the ground-support version with one axle and rubber tires was the most suitable one for antitank use. Madsen gun was popular in many roles, while it was most popular in antiaircraft use, they were commonly used in war ships with some being also used in aircraft and armoured vehicles. Among countries using 20-mm Madsen gun before or during World War 2 were Denmark, Sweden, Finland, Norway, Estonia, China, Czechoslovakia, Poland, Belgium, France and Germany. At one point or another about twenty countries issued this gun. Before World War 2 20-mm Madsen automatic cannon was also manufactured under license in France and Belgium.

PICTURE: 20 mm Madsen automatic gun with antitank mount seen from another direction. (Photo taken in Jalkaväkimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (109 KB).

As noted, this is the anti-tank / ground-support version of 20-mm Madsen automatic cannon, which had its own gun carriage version. Finland acquired 20-mm Madsen automatic cannon with large variety of gun mounts, both fixed and mobile. Finnish military used Madsen automatic cannon mostly as anti-aircraft gun, so with exception of the gun mount used in this version, all other guns were suited to be used against aircraft. While Finnish Navy had acquired first 20-mm Madsen anti-aircraft guns on its ships in early 1930's, Finnish military did not really start buying these guns in large numbers until during Winter War (11/1939 - 3/1940). During that war Finnish military was suffering from extremely serious shortage of antitank-guns, which sparked the idea of using these guns as antitank-guns. But because very limited number of 20-mm Madsen anti-aircraft guns in Finnish use at that time, this idea could not be implemented until during the last weeks of Winter War, when some 20-mm Madsen anti-aircraft guns were installed on improvised sledge mounts and saw some action as antitank-guns. Guns equipped with ground support / antitank-gun gun carriage were included to those gun acquired during Winter War, but like grand majority of 20-mm Madsen cannons ordered during Winter War they were not delivered until this war had already ended. This antitank-gun version known as 20 PstK/40 by Finnish military was also quite rare if compared to other versions in Finnish use. Finnish military had only about 20 guns of this version, while the total number of 20-mm Madsen cannons in use of Finnish military was about 360 guns.

When Continuation War (6/1941 - 9/1944) started 20 PstK/40 were issued to Finnish frontline troops as antitank-guns, and served in this use until being withdrawn from frontline service by March of 1942. While they had excellent rate of fire and due to their small weight had good mobility, their armour penetration capability was actually weaker than that of L-39 antitank-rifle. 20-mm Madsen automatic guns were firing from closed breech, due to which they had some tendency of over-heating, but this was probably lesser with this antitank-gun version than with anti-aircraft guns. The actual automatic cannon used in 20 PstK/40 seems to be same version of 20-mm Madsen, which was also used as anti-aircraft gun version, which Finnish Army referred as M/40 M. Some evidence suggests that

Once pulled off from frontline service these antitank-guns were issued to coastal troops and remained in their use until end of World War 2. Rate of fire, mobility and accuracy of Madsen guns were very good, hence they were apparently well suited for beach defence, in which their limited armour-penetration capability was not such a serious handicap. Finnish main manufacturer of 20 mm x 120 Madsen ammunition was by Tikkakoski, who made both AP-T and HE/HE-T ammunition in this calibre. Another Finnish manufacturer Oy Ammus manufactured small amounts of AP-T and HE-T ammunition for Madsen guns. Officially the last 20-mm Madsen guns remained in use of Finnish Armed Forces until year 1986.

 

25 PstK/34 and PstK/37 "Marianne"

(25 mm antitank guns M/34 and M/37 "Marianne")

PICTURE: 25 PstK/34 antitank-gun. Notice structure of the gun shield and flash hider. Photo taken in Niinisalo training centre. (SA-kuva photo archive, photo number 96376). CLICK THUMBNAIL TO SEE LARGER PIC (204 KB).

PICTURE: 25 PstK/37 antitank-gun with its gun crew. Photo taken in Hytti at July of 1941. (SA-kuva photo archive, photo number 24448). CLICK THUMBNAIL TO SEE LARGER PIC (266 KB).

Calibre:

25 mm x 194 R

Length:

392 cm (PstK/34)

Barrel length:

180 cm (PstK/34) / 181 cm (PstK/37) aka L/77

Weight in action:

496 kg (PstK/34) / 310 kg (PstK/37)

Rate of fire:

?

Muzzle velocity:

918 m/sec (PstK/34) / 900 m/sec (PstK/37)

Magazine:

None

Traverse:

37 degrees

Elevation:

-10 degrees, +25 degrees

Max. range:

1800 m (presumably direct fire)

Width:

105 cm (PstK/34)

Height:

109 cm (PstK/34)

Country of origin:

France

Ammunition types:

AP-T, AP (projectile 320 g, 750 m/sec)

Armour Penetration:

- "Guns vs Armour website" by D.M. Honner (AP-T, 920 m/sec):

Finnish use: Less than 40 used by Finnish troops in frontline use during last few weeks of Winter War. Another 200 bought during Interim Peace and used in frontline use during early Continuation War, until being replaced by more effective at-guns by mid 1942.

French M/34 antitank gun was product of Hotchkiss factory and developed in early 1930's. Its later designed competitor M/37 antitank gun was mainly manufactured by Puteaux factory. Both guns has same ballistics and same basic structure, in fact the largest main difference between the two was weight, which favoured M/37. Largest notable visible differences between the two are the structure of gun shield and wheels. Both guns used same ammunition. During German attack to France in 1940 these guns were the main antitank-gun types used by French Army. They proved to be accurate guns, and flash-hiders used in them made them quite difficult to spot, but their armour penetration capability and range were not good. The Germans captured both guns in large numbers in 1940 and used them in secondary roles as coastal defence and in some garrisons. Only ammunition types Finnish military used with these guns in battle were AP (armour piercing) and AP with tracer. This made them only antitank-guns in Finnish use without HE-ammunition (HE = high explosive). Anyway this was not much a shortcoming, because while high-explosive rounds are useful against enemy infantry and other soft targets, the 25-mm calibre was too small to make much of a difference. When each individual round had to be manually loaded to the gun the effect of resulting rate of fire combined with small 25-mm projectile probably just was not considered worthy for developing high-explosive round. In addition of AP and AP-T the complete ammunition inventory for this gun included also practice round (similar to AP but without hard steel core) and blank round. Ammunition was carried in boxes of 12 rounds.

Finland purchased 50 French 25-mm M/37 antitank guns during Winter War, but only 40 of them were delivered in February of 1940 through Norway. The remaining ten guns were captured by the Germans when they invaded Norway in spring of 1940. About half of the guns, which had arrived during Winter War saw frontline service during it and three of them were lost in battle. During Interim Peace the Germans offered Finland another 200 French 25-mm antitank guns that they had captured. This shipment arrived from Germany 10th of December of 1940 with S/S Hohenhörn and included:

  • 133 antitank guns M/34
  • 67 antitank guns M/37
  • When Continuation War started large number of 25-mm guns were issued to Finnish frontline troops, but soon their weak armour penetration capability made them outdated, so withdrawing them from frontline use started already early 1942. Report concerning antitank-guns used by Finnish Army dated February 1942 notes from these guns that: "Their armour-penetration capability is such, that they have no meaning as actual antitank-weapons..." The last of 25-mm antitank-guns were withdrawn from frontline use in year 1943. After the war they were kept warehoused until being declared obsolete in 1959. The remaining 225 guns were sold to Interarmco in 1960.

     

    37 PstK/36 Bofors

    (37 mm antitank gun M/36 Bofors)

    PICTURE: Swedish made 37 mm Bofors antitank gun. Notice the "waved" sides of gun shield used to make spotting the gun more difficult. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (137 KB).

    Calibre:

    37 mm x 257 R

    Length:

    304 cm

    Barrel length:

    174 cm (with muzzle brake) aka L/45

    Weight in action:

    375 kg

    Rate of fire:

    30 shots/min (maximum) / 12 shots/min (practical)

    Muzzle velocity:

    500 - 810 m/sec

    Magazine:

    None

    Traverse:

    26 degrees

    Elevation:

    -10 degrees, +25 degrees

    Max. range:

    7400 m (indirect fire) / 4500 m (direct fire)

    Width:

    109 cm

    Height:

    103 cm

    Country of origin:

    Sweden, manufactured also in Finland and Poland

    Ammunition types:

    AP-T, APHE, APHE-T, HE-T, HE, phosphorous (rare)

    Armour Penetration:

    - "Marskin panssarintuhoojat" (870 m/sec):

    - Finnish live fire testing year 1943 ("37 psav - Vj4", AP-T, 810 m/sec):

    Finnish use: This was the first purpose-build antitank-gun in Finnish use, but only 48 guns had arrived before Winter War. Another 66 guns imported from Sweden during Winter War, 10 Polish guns imported during Interim Peace and 355 guns from Finnish license production made it most typical at-gun in Finnish use during Winter War and early Continuation War. They were first transferred to other duties than antitank use and ultimately removed from frontline use by early 1944.

    Prototype of this light but effective (according standards of that time) antitank-gun was finished in year 1932. Its first version was named M/34 after the year it become ready to production. First country to order it was (delivery of 12 guns) was Netherlands in 1935. The Swedes themselves bought the first guns of this type in 1937 and called them 37 mm pkan M/34. During production new versions called M/38 was developed and replaced the old M/34 version in production. 37-mm Bofors at-gun was worthy competitor to German 3.7 cm Pak 35/36 in every category in late 1930's, so it achieved some commercial success. Among countries to which it was imported were Denmark, Finland, Great Britain, Poland, Turkey and Yugoslavia. Poland also acquired production license for these guns in 1936 and manufactured them under name Armata przeciw-panzerna wz. 36. German troops captured reasonably large number of 37-mm Bofors at-guns in Poland in year 1939 and renamed them as 3,7 cm Pak 36(p) before issuing them to their own troops. It is believed some of those guns in German use saw action against British troops in North Africa, where incidentally also British used their 37-mm Bofors at-guns. The main differences between Finnish, Polish and Swedish made guns of this type are in sides of gun shield (straight or "waved") and in wheel structure.

    PICTURE: Another pic of Swedish made 37 mm Bofors antitank gun. Notice the "OHOHOHOH..." pattern in tires, typically tires with this pattern were used in Finnish and Swedish made 37 PstK/36 guns, while usual tire pattern of Polish made guns had the "razorback"-pattern. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (132 KB).

    PICTURE: More closer look to systems of Swedish made 37 mm Bofors at-gun. Note original Swedish sight in left side of breech and semi-automatic breech mechanism using vertical sliding breech block. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (130 KB).

    Finland accepted 37 mm Bofors M/36 as new main antitank-gun October of 1938 from Bofors and order was made still in that same year. October of 1939 another batch of 24 guns were ordered and in January of 1940 yet another batch of 18 guns was ordered. Before Winter War Finland had received 48 guns of this type, during Winter War another 66 guns were delivered from Sweden (guns used by Swedish SFK voluntary force not included to these numbers). 37-mm Bofors at-guns bought from Bofors to Finland included both M/34 and M/38 versions. December of 1939 Finns also bought 20 Polish-made 37-mm K/36 at-guns from Hungary, but Germans managed to delay their delivery until summer of 1940.

    While none of the Finnish books or articles mention this some documents in Military Archives claim that additional 22 guns were ordered from Germany after Winter War. Presumably these 22 guns would have been delivered in August of 1941. If they were delivered they were likely Polish origin.

    PICTURE: One of the 20 Polish made 37 mm Bofors antitank guns in Finnish use. Notice the straight sides of gun shield and "razorback" tire pattern. This gun also has Finnish World War 2 era camo painted on it. (Photo taken in Panssarimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (169 KB).

    Finland also acquired license for production and two Finnish companies, Tampella and VTT (Valtion Tykkitehdas = State Artillery Factory) manufactured these guns. The two companies could have hardly been more different, but both were still newcomers when it came to manufacturing weaponry. Tampella was old privately owned limited liability company, whose Weapons Department established 1932 had before this been focused manufacturing mortars. In addition of manufacturing Brandt-Stokes mortars under license (also as sub-contractor of Brandt-Stokes) it had also developed its mortar designs. VTT (State Artillery Factory) was state-owned company established just February 1939 as manufacturing plant of heavy weapons for Finnish Armed Forces. Other factories, which played important role in manufacturing 37 PstK/36 in Finland were Lokomo and Crichton-Vulcan. As usual Lokomo Works was the manufacturer that supplied both Tampella and VTT the needed barrel blanks. Crichton-Vulcan manufactured parts made from heavy steel plates - mainly gun shield and most large parts needed for gun carriage. First Finnish-made guns rolled out of factories in summer of 1939.

    37 PstK/36 guns manufactured in Finland before Winter War:

    Manufacturer

    Amount

    Tampella

    48

    VTT

    32

    By end of 1939 Tampella and VTT had manufactured (the earlier listed pre-war guns included):

    Manufacturer

    Amount

    Tampella

    48

    VTT

    48

    Finnish plan (from year 1938) had been originally to provide antitank-gun platoon with 2 antitank-guns to each "field battalion" (battalion of infantry, at the time each Finnish infantry regiment had three of these battalions), but when Winter War started Finland was not even close of having the amount of antitank-guns needed for this. When Winter War begun in 30th of November 1939 Finnish Army had only 98 Bofors at-guns, while having 9 divisions and each of them typically having 10 "field battalions" (9 infantry battalions and one light battalion per division). So obviously the number of existing antitank-guns did not allow following that plan. What resulted then was an improvised solution, which did not really follow any pre-war plan. Antitank-gun platoons existing when the war begun went to frontline with the units, to which they belonged. When more guns became available new antitank-gun platoons were hastily equipped and trained in Antitank-gun Training Centre (Panssarintorjuntakeskus) located to town of Hämeenlinna. After receiving training of less than two weeks these new platoons were sent to frontlines and issued to various units. Shortage of antitank-rifles demanded the Finns to use their antitank-guns (also very limited in number) in immediate front-line during Winter War and this lead to high losses. By end of Winter War Finnish troops had received 222 guns of this type (this includes both guns acquired from Sweden and Finnish production), but at the same time about 60 of them had been lost in battle. So the number of guns did not really increase very much during Winter War.

    PICTURE: Finnish made 37 PstK/36. Notice streight sides of gun shield and tire pattern, which were typical to Finnish and early Swedish made guns. (Photo taken in Maneesi of Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (159 KB).

    When the Germans invaded Denmark and Norway in April of 1940, it quickly made the Swedes to realise how dangerous their situation actually was. Sweden needed to improve its military capability fast and asked some of the weapons it had delivered to Finland to be returned. Among weapons that Finland returned also were 20 Swedish 37-mm Bofors at-guns of Swedish manufacture. These 20 guns returned to Sweden included 7 guns that had arrived with Swedish-Norwegian SFK volunteer unit and 13 Finnish-manufactured guns, which Swedish Army named M/38 F. May of 1940 only 25 of the 114 guns delivered to Finland from Sweden still remained in Finnish use.

    The Finns were also having ammunition shortage with 37-mm Bofors antitank-guns during Winter War, because only 32,000 shells had been bought for these guns before the war. This soon proved to be much too little and further Swedish ammunition deliveries were not fast or large enough to remove the problem. To fix the situation domestic ammunition production was started in VTT (Valtion Tykkitehdas = State Artillery Factory) in December of 1939. But the production in VTT started slowly (only 1,680 shots made in December 1939) and the 18,000 shots it managed to make during Winter War failed solving the ammunition-shortage. During Winter War Finnish military ordered ammunition for these guns from Sweden almost on daily bases. Increased Finnish domestic ammunition production finally ended the ammunition shortage in year 1941. From that on Finnish military had plenty of ammunition for them.

    Finnish military used variety of sights with 37 PstK/36 antitank-guns. Some of the Swedish-made guns were delivered with Swedish optical sights and some have later been spotted in Finland also with German-made (Oigee and Carl Zeiss) optical sights. Polish-manufactured guns had Polish optical sight. These German-made optical sights may have originally belonged to Finnish-made, acquired later for them or even arrived with the Swedish or Polish-made guns. Acquiring suitable sights for guns manufactured in Finland with license proved problematic early on, so at least three kind of Finnish sights were used with them. The first "emergency-sight" seems to have been simple contraption, in which sights of rifle M/28-30 have been attached to piece of rifle barrel about 30-cm (12 inch) long. The second Finnish-made sight model used with these guns was also rather simple collimator sight. The third version was also collimator sight, which Tampella seems to have manufactured early 1940. It is reasonably certain that Finns succeeded acquiring optical sights for the license-manufactured 37 PstK/36 guns from Germany after Winter War, which might explain the Carl Zeiss and Oigee manufactured sights.

    Originally these guns had been designed for motorized towing, in other words they were intended to be towed with trucks or other suitable motor vehicles. However Finnish military also designed and introduced limber, which allowed the gun to be horse-towed. Only one horse was needed for towing the gun. While the Finnish pre Winter War Antitank-gun Platoons armed with these guns were all motorized, also horse-towed (antitank-gun) platoons started to appear during it and continued to exist also during Continuation War. The maximum towing speed for this gun was only 25 km/hour.

    PICTURE: 37 PstK/36 manufactured by Tampella in year 1940. This particular gun represents the last career phase of 37 PstK/36 as infantry guns. It has post-war "splinter" camo pattern, plaque with repair markings on its gun shield and triangle shape red rear reflector. One of the two lower armour plates is missing. (Photo taken in Bunkkerimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (209 KB).

    Finnish license production continued until year 1941, deliveries of 37 PstK/36 at-guns manufactured in Finland:

    Manufacturer

    1939

    1940

    1941

    Total

    VTT

    48

    7

    0

    55

    Tampella

    48

    152

    100

    300

    Total

    96

    159

    100

    355

    Notice: According some sources VTT manufactured 8 guns in 1940. In addition to guns listed above VTT manufactured also 33 of 37 Psv.K/36 (tank-gun version of 37 PstK/36 antitank-gun) in 1939 - 1940.

    During Winter War 37-mm Bofors antitank-gun was still powerful enough to knock out any Soviet tanks (only exception being the heavy tanks like KV tested during it) in use at that time. But during Continuation War new Soviet medium and heavy tanks proved to be too thick armoured for at-guns like 37-mm PstK/36. Officially last of these guns were not removed front line use until early 1944, but typically they had not been used as antitank-weapons for quite some time before that. Around 1942 - 1944 they saw mostly use as direct-fire support weapons used against knocking out Soviet bunkers, machinegun-nests, direct-fire guns etc. With their small weight, high rate of fire and good high-explosive rounds they proved well-suited to this kind of use. Year 1944 their number was still so large (about 250) that Finnish Armed Forces wanted to find new uses for them, so they continued to serve as infantry guns until year 1986.

    Losses of 37 PstK/36 antitank-guns guns during period 9th of June - 7th of July 1944:

    Unit:

    Losses:

    III Army Corps

    11

    IV Army Corps

    9

    V Army Corps

    7

    Aunus Group

    23

    Total:

    50

    Finnish ammunition manuals list following ammunition for 37 PstK/36 antitank-gun and 37 Psv.K/36 tank gun:

  • 37 tkrv-Vj6-27/30 K/36 pr.: TNT-filled HE-tracer round, projectile weight without fuse 725 g, muzzle velocity 815 m/sec.
  • 37 tkrv 27/30-R K/36 pr.: TNT-filled HE round, projectile weight without fuse 575 g, muzzle velocity 830 m/sec.
  • 37 pstkr 27/34-ps R K/36 pr.: TNT-filled APHE round, projectile weight with fuse 740 g, muzzle velocity 810 m/sec.
  • 37 ps R 27/34-Vj6 K/36 pr.: APHE-T version of the previous APHE round, projectile weight with fuse 740 g, muzzle velocity 810 m/sec.
  • 37 pstkr 27/34-ps R K/36 pp.: Another TNT-filled APHE round, projectile weight with fuse 700 g, muzzle velocity 830 m/sec.
  • 37 pstkr 27/34-ps R K/36 pr.: Another TNT-filled APHE-T round, projectile weight with fuse 740 g, muzzle velocity 810 m/sec. Added to ammunition manuals in end of October 1941
  • 37 psav-Vj4 K/36 pr.: AP-T round, projectile weight with fuse 740 g, muzzle velocity 810 m/sec.
  • 37 psav-Vj4K/36 p.: Another AP-T round with shorter projectile, projectile weight with fuse 740 g, muzzle velocity 810 m/sec.
  •  

    37 PstK/37 and PstK/40

    (37 mm antitank guns M/37 and M/40)

    (3.7 cm Pak 35/36)

    PICTURE: 37 PstK/37 antitank gun. This gun is painted with what might extremely faded example of Finnish wartime camo.(Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (108 KB).

    Calibre:

    37 mm x 249 R

    Length:

    350 cm

    Barrel length:

    166 cm aka L/45

    Weight in action:

    330 kg / 450 kg (depending source)

    Rate of fire:

    12 - 15/min (practical)

    Muzzle velocity:

    500 - 1030 m/sec

    Magazine:

    None

    Traverse:

    60 degrees

    Elevation:

    - 8 degrees, + 25 degrees

    Max. range:

    6800 m (indirect fire)

    Width:

    160 cm

    Height:

    120 cm

    Country of origin:

    Germany

    Ammunition types:

    APHE (Pzgr.) 680 g projectile 760 m/sec

    (APCR (Pzgr.40) 354 g projectile 1030 m/sec - not in Finnish use)

    HE 690 g projectile 710 m/sec

    Stielgranade 41 HEAT bomb 8500 g 110 m/sec (1942)

    Armour Penetration:

    - "Panzerabwerhgeschütze etc":

    - "Small arms, artillery and special weapons of the third reich":

    - "Twentieth Century Artillery":

    - "Deutsche and alliierte heereswaffen 1939 - 1945":

    - Finnish live fire testing year 1943 ("37 pspekr 22/27-ps", German APHE, 710 m/sec):

    Finnish use: Germans delivered 200 guns in 1940 - 1941 to Finland. With little help from 5,000 Stielgrenade HEAT bombs acquired in 1942 they remained in Finnish use until end of Continuation War, however in 1943 - 1944 large number of these guns were replaced with more heavy-calibre ones.

    Development of 37-mm antitank gun started in Rheinmetall factory in 1925 and first prototypes were tested in 1928. First delivery of 264 horse-towed 3,7-cm at-guns was issued to German Army in 1932, but this early version did not see large-scale production, as changes were made to guns mount already in 1934. The new very much improved mount and rubber-wheels allowed the new version to be towed with motor vehicles also. Some more changes were introduced to guns little-by-little around 1935 - 1936, these included change in manufacture method of gun barrel, replacing existing equipment boxes with bigger ones and improvements in towing system and tires. 3.7 mm Pak (shorter version from "PanzerAbwerhKanone") as Germans called it was reasonable export success, countries to which it was exported before World War 2 included Soviet Union, China, Italy, Netherlands, Greece and Estonia. Already before World War 2 these guns saw use in Chinese-Japanese war and Spanish Civil War. in the same time German 37-mm at-gun also had large affect to antitank-gun developments of many other countries, especially US 37-mm and Soviet 45-mm at-guns were clearly based to its structure.

    Before starting of World War 2 some 11,200 German 3.7 cm Pak were manufactured and by 1941 the number reached 15,000. French and British heavy tanks which the Germans met first time in France in summer of 1940 were already quite resistant to their fire, but it was the large amounts of T-34 and KV-1 tanks fielded by Soviets that finally proved too much for 3.7 cm Pak to handle. The Germans had made good work with development of ammunition used in this gun introducing tungsten-cored Pzgr.40 APCR-ammunition and large sized Stielgranade 41 HEAT-bomb, but new tanks were too thick-skinned even for Pzgr.40 and short range of Stielgrenade 41 made it basically an emergency weapon with questionable effectiveness. So, production of 3,7 cm Pak ended in March of 1942.

    PICTURE: Closer look to systems of 37 PstK/37 antitank gun. Sight of this gun seems to be missing. Also note breech system with semi-automatic horizontal sliding breech block typical to German at-gun designs. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (175 KB).

    The Finns had been very much aware of German 37-mm antitank-gun already before World War 2, but Bofors gun had been favoured before Winter War and during Winter War Germany in accordance with its agreements with Soviet Union (generally) did not sell weapons to Finland. However, as soon as the Interim Peace following Winter War started situation changed and first delivery of 50 guns from Germany was made via Hungary. The origin of these first 50 guns is somewhat uncertain. It seems possible that since this first delivery, which arrived within few weeks after ending of Winter War (in other words: late March - early April 1940), the Germans probably tried to secret it from the Soviets. However this seems somewhat unlikely, since Germany apparently did not gain interest of selling weapons to Finnish military until several months later. In many Finnish documents the source for these 50 guns have also been marked as Spain. Hence the second and probably more likely theory is that the guns may have indeed come from Spain with Josef Veltjens (who had been equipping Nationalist Spain during Spanish Civil War 1936 - 1939) being behind this deal. Veltjens was a World War 1 German fighter ace, who later became gun merchant and during World War 2 served Lieutenant Colonel of German Luftwaffe. He had long-standing relationship with Finnish military and had been covertly supplying Finland with military equipment during Winter War. Veltjens also had close relations to Hermann Göring and was Göring's emissary to Finland for negotiations held in August of 1940, as a result of which Germany again started officially selling weapons to Finnish military. The second delivery batch containing 100 guns arrived directly from Germany in September of 1940. The third and final delivery batch of 50 guns arrived from Germany in June of 1941.

    German military did not separate different versions of their Rheinmetall 37-mm antitank gun to sub-models, they all were simply called 3,7 cm Pak. The Finns did the other way and divided these guns to two models - PstK/37 and PstK/40. The main factor separating the two gun models in Finnish use was structure of gun barrel, which had changed when Germans had made changes to ease its manufacturing. Gun barrel of K/37 had an obvious jump in barrel thickness about middle length of barrel, while in gun barrel of K/40 the angle of change in barrel thickness was constant in full length of barrel. The Finns bought large numbers of spare parts for these guns - the same spare parts fit to both of these gun models. Due to this the wartime repairs actually changed most of the Finnish Army PstK/37 and PstK/40 guns to mixed versions referred as PstK/37-40 and PstK/40-37. Apparently the guns delivered to Finland were equipped with primary optical sight and collimator-type backup sight. Finnish ammunition inventory for these guns does not seem to have included Pz.Gr 40 APCR-round. But to keep up with tank development Finnish Army bought 5,000 Stielgrenade 41 HEAT-bombs to be used with them. These HEAT-bombs arrived in August - November of 1942, they were used first for training and later saw also combat-use. Year 1944 Finnish Armed Forces GHQ even at one point decided to give every division at least one antitank-gun company armed with 37-mm German at-guns and Stielgrenade 41. The Finns kept using these German 37-mm antitank-guns until end of World War 2. According wartime plans more modern 75-mm antitank-guns would have slowly replaced them in frontline antitank-use, but the new heavy antitank-guns were not available in numbers large enough to totally replace them before end of the war. Once Continuation War ended in September of 1944, so did the career of these guns as antitank weapons. About 140 of these guns survived World War 2 and remained warehoused for possible use until late 1970's. During that time they saw some training use as infantry guns. Around 1982 - 1984 most of them were sold and exported.

    Losses of 37 PstK/40 antitank-guns during period 9th of June - 7th of July 1944:

    Unit:

    Losses:

    III Army Corps

    5

    V Army Corps

    22

    Total:

    27

    PICTURE: German made 37 PstK/40 antitank gun. (Photo taken in Panssarimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (154 KB).

    Stielgranade 41:

    As other antitank-guns designed before World War 2 during the war also this became outdated due to ever increasing armour protection of new tank designs. German military had huge number of these guns, so they decided to try keeping them at least somewhat up-to-date by developing new mmunition. One of these development was rifle grenade like Stielgenade 41 HEAT-bomb. The Germans manufactured about 636,000 Stielgrenade 41 HEAT-bombs for 37-mm guns in 1942 - 1943. Compared to German wartime total ammunition production for these antitank-guns (over 11.2 million rounds) the number was fairly small. But, it was the ammunition model that still allowed these guns to have some change to fight against new medium and heavy tanks, even if it can be very much considered as an emergency weapon. Basically Stielgrenade 41 was like a very large rifle grenade equipped with high explosive anti-tank (HEAT) warhead. It was fired from end of gun barrel with blank cartridge and could be used both in German 37-mm AT-guns and AA-guns. HEAT warhead was capable of penetrating 180-mm of armour (90-degree angle of impact), making it dangerous to any tank. However, as this HEAT-bomb weight some 8.5 kg and had muzzle velocity of only 110 meters/second, it could be used only from fairly short distance. Maximum range for it was about 600 meters and the effective range only about 300 meters or so.

    Although even the effective range of 300 meters may have been optimistic estimate. According Finnish tests already fromshooting distance 250 meter distance the average dispersion was quite considerable:

  • Vertical dispersion: 71 cm
  • Horizontal dispersion: 67 cm
  • When flight time of this projectile from that distance (250 meters) was also 2.4 seconds, hitting a fast moving tank was not exactly easy. Using Stielgrenade 41 demanded one of the crew to go in front of the gun and push the grenade to end of barrel for each shot, so firing rate was not exceedingly high either. To make things even worse Finnish experiences suggest that this ammunition had problems related to quality control. Finnish Army acquired 5,000 rounds of Stielgrenade 41, which arrived to Finland with S/S Ariel in 26th of August 1942. Finnish Army tested the ammunition soon after its arrival by test-firing 22 rounds - test report noted that in 5 rounds out of 22 tested, propellant burned only partially, resulting HEAT-bomb flying only few meters from gun barrel before hitting the ground and when fired one round blow up rupturing the gun barrel. Even if this gun-barrel rupture with Stielgrenade 41 may have been one of a kind with Finnish Army, shooting this ammunition during training was forbidden in Finland and this ammunition type was reserved only for combat use. Reason for the partial burning of propellant proved to be that in blank cartridges used to fire Stielgrenade 41, the grease used to seal the primer of had leaked into detonator and degraded it. When Finnish Army inspected the blank rounds that had arrived with Stielgrenade 41 this quality control issue was discovered in over 1,500 blank rounds and lid used to seal off head of the blank round was not properly tightened in over 1,000 rounds. Hence less than half of the delivered ammunition was actually in working order as delivered. It remains uncertain in what extent Finnish troops actually used Stielgrenade 41 in combat.


    SOURCES:

    Werner Haupt: Panzerabwehrgeschütze 3,7 cm - 5,0 cm - 7,5 cm - 8,8 cm-Pak 1934 - 1945 ohne Selbstfahrlafetten.

    Alex Buchner: Deutsche and alliierte heereswaffen 1939 - 1945.

    Erkki Käkelä: Marskin Panssarintuhoojat.

    Risto Erjola: Aseiden valmistus Suomessa vuosina 1939 - 1945

    Article of Markku Palokangas: Anti-tank guns used by Finnish Army (Journal of Military History 17).

    Article of Markku Palokangas: Sotiemme aseveteraanien myöhemmät vaiheet (Ase-lehti magazine vol. 2/95).

    Article of Markku Palokangas: 1944 aseiden vuosi Suomen historiassa (Ase-lehti magazine vol. 6/94).

    Article of Risto Erjola: Ampumatarvikkeet sotien 1939 - 1945 aikana Suomessa (Tiede ja Ase, Suomen sotahistoriallisen vuosiseuran julkaisu N:o 48, 1990).

    Article of Esa Paanen: Suomessa käytetyt panssarintorjunta-aseiden patruunat (Ase-lehti magazine vol. 6/2003).

    Pekka Kantakoski: Punaiset panssarit.

    Jyri Paulaharju: Itsenäisen Suomen kenttätykit 1918 - 1995.

    Article of Lauri Harvila: Panssarintorjunta-aseet (Kansa taisteli magazine vol. 10/1976).

    Terry Gander and Peter Chamberlain: Small arms, artillery and special weapons of the third reich.

    Guns vs Armour by D.M. Honner

    Chris Chant: Artillery of World War II.

    Ian Hogg: Twentieth-Century Artillery.

    Battles of Winter War website Special thanks to its webmaster Sami Korhonen.

    Military manual: 20 mm:n konetykki Madsen (published 1940).

    Military manual: 25 mm:n panssarintorjuntakanuuna malli 1934.

    Military manual: 37 mm panssarintorjuntakanuuna vuodelta 1936 (printed 1939).

    Military manual: 37 mm:n pst. kanuunaopas, Saksal. mallit M/37 ja m/40 (printed 1941).

    Military manual: Ampumatarvikenimikkeistö by Puolustusvoimien Pääesikunta Taisteluvälineosasto (printed 1941).

    Military manual: Lyhennetty tykistön ampumatarvikenomenklatuuri (printed 1939).

    Military manual: Jalkaväen Ampumatarvikkeet I by Puolustusvoimien Pääesikunta Taisteluvälineosasto (printed 1941, updated until September 1944).

    Taisteluväinesotavarustuksen kuvasto. Mittaus-, havainto-, suuntaus- ja tätäyskalusto III/43.

    Finnish military archives, archive reference T19011

    Finnish military archives, archive reference T19043

    Finnish military archives, archive references T20206/F9, /F10 and /F11

    Special thanks to Sotamuseo (Finnish Military Museum), Helsinki.

    Special thanks to Panssarimuseo (Finnish Armour Museum), Parola.

    Special thanks to Jalkaväkimuseo (Finnish Infantry Museum), Mikkeli.

    Special thanks to Bunkkerimuseo (Bunker Museum), Virolahti.


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