FINNISH ARMY 1918 - 1945: ANTITANK GUNS PART 1 (original) (raw)

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).

(*) 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.

(***) APC-T round 20 psav-Vj5 was added to Finnish Army ammunition manuals in June of 1942. It had 154-gram armour piercing capped projectile with 5 second tracer and had 775 m/sec muzzle velocity. According manuals this ammunition type was primarely intended for antitank-gun version of 20-mm Madsen, although it could be used also in 20-mm Madsen anti-aircraft guns.

Armour Penetration:

- Results of Finnish test firing in 1941:

| distance | hitting angle | penetration | | ---------- | --------------- | ------------- | | 200 m | 60 degrees | 20 mm | | 500 m | 60 degrees | 16 mm |

- "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 gunsin 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 based on Madsen light machinegun, 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 auto fire. Weapon had several gun mount options, but from these the ground-support version with one axle and rubber tires was the one that was best suited for antitank role. 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 Two 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 practically all gun mounts used with 20 mm Madsen in Finland had been designed primarely for anti-aircraft role - with the notable exception of the gun mount used with this gun. While Finnish Navy had acquired first 20-mm Madsen anti-aircraft gunson 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 Winter War Finnish military was suffering from extremely serious shortage of antitank-guns, which sparked the idea of converting 20 mm Madsen guns existing in Finnish inventory into antitank-guns. But because there was also shortage of anti-aircraft guns and 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. Dozen guns equipped with ground support / antitank-gun gun carriage were included to 20 mm Madsen guns acquired during Winter War, but like grand majority of Madsen guns ordered during Winter War they were not delivered until the war had already ended. This antitank-gun version known as 20 PstK/40 by Finnish military was also quite rare In Finnish if compared to Madsen anti-aircraft gun. Finnish military apparently had at total only about twenty 20 PstK/40 guns, while the total number of 20-mm Madsen cannons in use of Finnish military was about 360 guns.

PICTURE: 20 PstK/40 could also be used without tires and their axle. Finnish coastal artillery used this gun for beach defence on Island of Valamo / Valaam on Lake Laatokka / Ladoga in June of 1942. Photographed by K. Kivi. (SA-kuva photo archive, photo number 95021). CLICK THUMBNAIL TO SEE LARGER PIC (114 KB).

When Continuation War (6/1941 - 9/1944) started 20 PstK/40 were issued to Finnish frontline troops as antitank-guns and served in that role 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 was similar 20-mm Madsen automatic cannon used as anti-aircraft guns.

Once withdrawn from frontline service as antitank-guns, these 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. In addition they had good selection of ammunition for variety of targets. Finnish main manufacturer of 20 mm x 120 Madsen ammunition was by Tikkakoski, who produced AP-T and HE/HE-T ammunition in this calibre. Another Finnish manufacturer Oy Ammus manufactured AP-T and HE-T ammunition for Madsen guns in more limited scale. 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")

(Canon de 25 mm semi-automatique mle 1934)

(Canon de 25 mm semi-automatique mle 1937)

PICTURE: 25 PstK/34 antitank-gun. Notice structure of the gun shield, flash hider and open ammunition box. Photographed by K. Kivi in Häsälä in July of 1941. (SA-kuva photo archive, photo number 27890). CLICK THUMBNAIL TO SEE LARGER PIC (204 KB).

PICTURE: 25 PstK/37 antitank-gun with its gun crew. Notice gun shield, which has three parts and when diassembled can folded to in both sides of the gun for transport. Photo taken by Sikanen in Hytti at July of 1941. (SA-kuva photo archive, photo number 24448). CLICK THUMBNAIL TO SEE LARGER PIC (266 KB).

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 antitank-guns in 1942 - 1943.

These two are French antitank-guns developed in 1930's. Both guns has same ballistics but otherwise differed in structural design and French Army apparently intended them to be issued to different unit types. Antitank-gun mle 1934 was product of Hotchkiss factory, whom had introduced first protypes of the gun already in 1920's, while mle 1937 was product of Puteaux (APX) arsenal. Both guns have split gun mounts with split trail and had sponge rubber tires, but have some structural differences and notable weight difference, with mle 1934 structurally more traditional being much heavier than mle 1937, for which light weight seems to have been a major design priority. French Army intended antitank-gun M/34 for specialised antitank units and it was designed for motorized towing, but the gun's structural design apparently proved poorly suited for that with maximum towing speed being limited to mere 15 km/hour. Antitank-gun mle 1937 was intended be issued infantry fire support units of French Army and designed be also for horse-towing if needed. Both guns have breech system with vertical sliding breech block, which as usual is what was at the time considered as "semi-automatic" - after shot is fired the breech system extracts cartridge case and leaves breech open for manual insertion of the next round. The two guns also have identical ballistics, use very similar large funnel flash hiders and have telescopic sight with 4X magnification as primary gun sight. Recoil systems used in them appear to be bit different, with mle 1937 having simpler design with hydraulic buffer and visible spring recuperator place around gun barrel. From these guns mle 1934 was manufactured in much larger numbers than mle 1937 - the total production of mle 1934 was either 4,225 or 4,400 guns total (*), while the total production of mle 1937 was only 1,285 guns.

(*) Conficting sources suggest total of 4,225 or 4,400 guns.

PICTURE: Antitank-gun platoon with its 25 PstK/34 antitank-guns. Photographed by 2ndLieutenant K. Purontaka in Ruokolahti in July 1941. (SA-kuva photo archive, photo number 48953). CLICK THUMBNAIL TO SEE LARGER PIC (115 KB).

During German invasion of France in year 1940 these guns were the main antitank-gun types used by French Army. They proved to be highly accurate guns and flash-hiders used in them made the guns quite difficult to spot, but their armour penetration capability was not particularly great and effective range was not that good either. In addition to which the light weight design of mle 1937 in particular suffered from durability issues. The guns also saw limited use with British Army in France (with British Expeditionary Force) and Norway. Small number of guns also saw use with Italian Army in North Africa and Germany apparently sold some 150 guns to Spain in year 1943. The Germans captured both guns in large numbers in 1940 and used them in secondary roles as coastal defence and in use of some garrisons. German inventory names for the guns were _2,5 cm Panzerabwehrkanone 112 (f)_and 2,5 cm Panzerabwehrkanone 113 (f).

While these guns were still effective in year 1939, development of new more heavily armoured tanks during World War 2 soon made them obsolescent. The problem was exacerbated by the limited ammunition selection available for these guns, which made it impossible for shift them into many other roles. 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 inventory without HE-ammunition (HE = high explosive). Anyway these were only ammunition available for the guns for other countries as well and this was not much a major shortcoming in a sense, because while larger calibre high-explosive rounds are useful against enemy infantry and other soft targets, 25-mm calibre projectile is too small to make much of a difference in manually loaded gun. 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. In addition of France and Germany these 25-mm French antitank-guns saw also limited use with British Army in France and Norway in year 1940.

PICTURE: 25 PstK/37 gun photographed during inspection in July of 1942. This particular gun was on Island of Valamo / Valaam, which means it was in use of coastal defence. Photographed by K. Kivi. (SA-kuva photo archive, photo number 97976). CLICK THUMBNAIL TO SEE LARGER PIC (180 KB).

Finland purchased 50 French 25-mm M/37 antitank guns during Winter War, but only 40 of them were delivered in February of 1940 via Norway. The remaining ten guns along 10,000 rounds of ammunition had arrived by ship to Norway in 12th of March and were captured by the Germans when they invaded Norway in April of 1940. About half of the guns, which had arrived during Winter War saw frontline service already during it and three guns were lost in battle. About 25,000 rounds of ammunition were received with the 40 guns delivered during Winter War. During Interim Peace (1940 - 1941) the Germans offered Finland another 200 French 25-mm antitank guns, which they had captured. Due to being in dire need of antitank-guns Finland accepted the offer and bought the guns. The 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

Circa 1940 - 1941 Finnish Army gathered feedback about various weapons from military units that had used them during Winter War. The feedback about these guns proved to be somewhat conflicting. The positive observations included the guns being easy to use with simple breech system and good gun sights and largely due to the flash hider difficult to spot. Negative aspects were that the in general the gun was found to be too heavy for its armour penetration capability and in general other mechanical devices except the breech mechanism were complicated and structurally delicate. It seems to have been quite clear already at that point, that the guns were about to become obsolescent quite soon, but since no better antitank-guns were available, Finnish Army had to make the ends meet with what it had.

PICTURE: 25 PstK/37 gun in beach defence role in Vitele (northern shore of Lake Laatokka / Ladoga). Notice white and grey camouflage paint on the gun and soldier on the right holding a round. Photographed by Military official K. Kivi in January of 1943. (SA-kuva photo archive, photo number 117564). CLICK THUMBNAIL TO SEE LARGER PIC (180 KB).

When Continuation War started in June of 1941 large number of French 25-mm antitank-guns were issued to Finnish frontline troops, but with introduction of new Soviet tanks like KV-1 and T-34 their weak armour penetration capability soon made them outdated. So withdrawing them from frontline use started already in early 1942. By that time the earlier mentioned durability issues and delicate nature of certain mechanical systems had apparently already caused large number of guns being withdrawn for repairs, so in early 1942 only about 100 of the guns remained in frontline use. By early 1943 the total number of guns remaining in use of frontline troops had dropped to few dozen and most of the guns had been transferred to coastal defence, which apparently used them for beach defence. Report concerning antitank-guns used by Finnish Army dated February 1942 notes from the 25 mm French 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 were mothballed for possible further use until being declared obsolete in year 1959. The remaining 225 guns were sold to Interarmco that year and exported in year 1960. The guns sold to Interamco included 125 guns M/34 and 100 guns M/37.

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).

Armour Penetration:

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

Finnish Army manual for this gun:

- Results of test firing done in 1943:

- 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, 20 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.

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. Also notice leather lined pads on top of gun's split trail - the gun shield is intentionally small, but does not offer much protection unless the gunner and loader operate the gun while laying on their stomachs on top of those pads as intended. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (132 KB).

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 the 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 visual differences between Finnish, Polish and Swedish made guns are in design of gun shield (straight or "waved") and in wheel patterns.

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). It is not known if acquistion of eight guns Ragnar Nordström for troops defending northern Finland are included to these numbers. 37-mm Bofors antitank-guns bought from Bofors to Finland had both M/34 and M/38 guns. December of 1939 Finns also bought 20 Polish-made 37-mm K/36 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:

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

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).

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 such 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 antitank-guns, while having nine divisions and each of them typically having ten "field battalions" (nine infantry battalions and one light battalion per division). So obviously the total 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 led 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 total number of guns in use at any given moment did not really increase very much during Winter War.

PICTURE: Well camouflaged Bofors antitank-gun somewhere north of Lake Laatokka / Ladoga during Winter War. Gun has been camouflaged with white fabric and number of spruce branches. Gun crew is wearing improvised snow camo ponchos instead of proper snow camo suits on top of their greatcoats. While they are otherwise quite well equipped clothing-wise they do not have fur hats as they should and are wearing field caps M/36. Photographer unknown. (SA-kuva photo archive, photo number 1737). CLICK THUMBNAIL TO SEE LARGER PIC (123 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.

PICTURE: 37 mm Bofors antitank-gun in Finnish use during Continuation War. Gunner is laying on his stomach on top of the gun's left trail and another soldier is handing over a round to loader. Photographed by Military official V. Hollming in line of Vermajoki River in Lapland presumably in winter of 1942 or 1943. Three of the soldiers appear to be wearing Swedish Army livpäs fur coats, which Finnish Army issued only in very limited numbers. Gunner and loader have Italian m/33 steel helmets, while other two soldiers appear to have what are likely German m/35-40 helmets. (SA-kuva photo archive, photo number 36995). CLICK THUMBNAIL TO SEE LARGER PIC (123 KB).

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.

PICTURE: Horse-towed 37 PstK/36 antitank-gun in Kiviniemi (Carelian Isthmus). This was the standard equipment set that Finnish Army used for horse-towing Bofors antitank-gun - single horse and purpose-built limber. The soldier looking into camera has captured Soviet M/91-30 rifle. Photographed by T. Nousiainen in August of 1941. (SA-kuva photo archive, photo number 36995). CLICK THUMBNAIL TO SEE LARGER PIC (93 KB).

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.

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

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. About 250 of the guns survived World War 2 and after the guns that were worst shape had been scprapped or disassembled for spare-parts there were still 242 guns in inventory in April of 1946. Even if they were no longer useful as antitank-weapons the total number of guns was still so large that Finnish Armed Forces wanted to find new use for them, so they continued to serve as infantry guns (intended to be used as direct-fire fire-support). When used as infantry guns, the guns referred as 37 jvk/36 (37 mm infantry gun model 1936) . Year 1985 Finnish inventory contained 202 of 37 jvk/36. The guns was declared obsolete in year 1986. About 25 guns were transferred to various museum collections and number of guns were sold to collectors with some guns also being exported.

PICTURE: 37 PstK/36 manufactured by Tampella in year 1940. This particular gun represents the last career phase of 37 mm Bofors as infantry gun. 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).

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

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).

Armour Penetration:

- "Panzerabwerhgeschütze etc":

Pzgr.39 AP round (745 m/sec):

Pzgr.40 APCR round (tungsten core, 1030 m/sec):

Stielgrenade 41 HEAT bomb:

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

Pzgr.39 AP round (762 m/sec):

Pzgr.40 APCR round (tungsten core, 1030 m/sec):

Stielgrenade 41 HEAT bomb (110 m/sec):

- "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, torsion suspension and rubber-wheels allowed the new version to be also towed with motor vehicles. 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. Three -part upper section of the gun shield could be folded down if needed and the gun was equipped with optical sight that had either 1X or 1.1 X magnification. 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, with Soviet 45-mm at-guns in particular being clearly based to its structural design.

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).

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 Stielgrenade 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: Finnish gun crew photographed manhandling German 37 mm antitank-gun on a cobblestone road in region of Troitsa. These guns were normally towed with motor vehicles, but were light enough that could be manhandled for short distances on this sort of good ground with relative ease. The soldier partly obscuring the gun has captured Soviet M/91-30 rifle. Photographed by Kim Borg in September of 1941. (SA-kuva photo archive, photo number 45809). CLICK THUMBNAIL TO SEE LARGER PIC (100 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.

PICTURE: Well camouflaged 37 PstK/37 antitank-gun with its gun crew in Rukajärvi region in March of 1942. Photographed by Military official V. Hollming. (SA-kuva photo archive, photo number 76739). CLICK THUMBNAIL TO SEE LARGER PIC (118 KB).

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 mothballed 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:

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

Stielgrenade 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 Stielgrenade 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. Due to these obvious issues Finnish Army banned shooting Stielgrenade 41 for training purposes and this ammunition type was reserved only for combat use. Investigation that revealed that the reason behind the partial burning of propellant was that in blank cartridges used to fire Stielgrenade 41, the grease used to seal the primer used in these cartridges of had leaked into detonator and degraded it. When Finnish Army inspected all the blank rounds for 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 also found not to be properly tightened in over 1,000 rounds. Hence less than half of the delivered ammunition was actually in working order. It remains uncertain in what extent Finnish troops actually used Stielgrenade 41 in combat. However feedback suggests that also frontline soldiers serving as gun crews of 37-mm German antitank-guns had noticed these problems and did not really have much trust for Stielgrenade 41. According inventory list created in 19thof September 1944 , in other words right after Continuation War and hard battles fought in 1944, out of 5,0000 Stielgrenade 41 originally bought from Germany there were 3,964 in inventory from which 3,508 were stored in depots, while only 456 were in military units.

SOURCES:

Werner Haupt: Panzerabwehrgesch�tze 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.

Chris Chant: Artillery of World War II.

Ian Hogg: Twentieth-Century Artillery.

Battles of Winter War website (website no longer active) and 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 National Archives, archive reference T18461/9

Finnish Military Archives, archive reference T19011

Finnish Military Archives, archive reference T19043

Finnish Military Archives, archive references T20206/F9, /F10 and /F11

Finnish National Archives, archive folder T-21417/1 c:1 sal: Classified briefings and statistics of Ordnance Supply in 1940 - 1944.

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.

Last updated 18th of May 2023
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