MACHINEPISTOLS, PART 1:

Bergmann and Suomi

 

7,65 mm Bergmann M/20:

PICTURE: 7,65 mm Bergmann M/20 submachine gun. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (40 KB).

Calibre:

7,65 mm x 21 Parabellum (.30 Luger)

Length:

815 mm

Barrel length:

200 mm

Weight:

4,2 kg

Fire-rate:

600/minute

Magazine:

box: 50

Magazine weight:

0,30 kg

Official abbreviations:

"7,65 kp/Bergmann"

Country of origin:

Switzerland

Prototype:

1916 (first version)

Production:

In Switzerland 1920 - 1927 (made in several countries).

Finnish use: Suojeluskunta (Finnish Civil Guard) acquired these submachine guns and used them in between 1922 - 1939. For Winter War (1939 - 1940) the great majority of Suojeluskunta weaponry was transferred to Finnish Army, among them these submachine guns were issued to Finnish Army front-line troops during Winter War (1939 - 1940). During Continuation War (1941 - 1944) coastal troops and home-front troops used them.

During World War 1 Hugo Schmeisser developed SMG MP/18-I, which German weapons factory of Theodor Bergmann started manufacturing in year 1918. The German Army soon accepted the weapon and Bergmann factory manufactured some 35,000 (or 25,000 depending source) by the end of Wolrd War 1. This weapon was the first practical machinepistol/submachine gun and even if German Army managed to issue less than 10,000 before end of World War 1 the weapon gained such a reputation that Versailles peace treaty ending the war especially listed submachine guns as weaponry banned from German Armed Forces. The original MP/18-I submachine gun had a weak point in form of magazines, which were far from ideal: It used so-called snail-drum magazines, which Tatarek and Von Benkö had originally developed for artillery version of Parabellum P-08 pistol).

Soon after World War 1 Schmeisser developed Bergmann factory improved version of MP/18-I, which used box magazines. Year 1920 Bergmann sold manufacturing license of this improved MP/18-I now known as Bergmann to Swiss weapons factory S.I.G. (Schweitzerische Industrie-Gesellschaft). After making the deal S.I.G. started manufacturing Bergmann submachine guns in several calibers. S.I.G. manufactured Bergmann submachine gun was exported to several countries including Japan, China and Finland between 1920 - 1927. The Japanese and Chinese Bergmann submachine guns were made in 7,63 x 25 Mauser. Also Estonian Tallinn model 1923 submachine gun manufactured in only small numbers was directly based to MP/18-I. Production of Bergmann submachine guns in S.I.G. factory ended year 1927, S.I.G. offered introduced improved version in 1930, but with very little success. So S.I.G. started producing MKMO submachine gun (which was later developed to MKMS machinepistol). Later in Germany the development of improved MP/18-I led to development of MP/28-II submachine gun.

Finnish Army was not interested about submachine guns in early 1920's, like most Armies of that time it doubted if this type of weapon would be useful to military. However, Suojeluskunta (Finnish Civil Guard) didn't have no such doubts and it bought first 1,000 Bergmann submachine gun already year 1922. By 1932 Suojeluskunta had bought 1,415 submachine guns of this model. Around that point Suomi M/31 replaced Bergmann in acquisitions of submachine guns. Once Finnish Army finally had become convinced about the excellent qualities of Suomi M/31 also Suojeluskunta decided to follow its example and from that on acquire Suomi M/31 submachine guns instead of Bergmanns. When Winter War begun Suojeluskunta Bergmanns were transferred to Finnish Army, which had serious shortage of automatic weapons. Finnish Army issued them to frontline troops for Winter War. Additional 108 Bergmann submachine guns were bought from Switzerland also during Winter War. 100 of them were the same 7.65 mm x 21 Parabellum calibre weapons like the earlier acquired Suojeluskunta Bergmanns, but eight seems to have been 9 mm x 19 Parabellum calibre version. Helsinki-based company Ilmakunnas acted as go-between in this deal in which the weapons arrived by very long route via Le Havre and Stockholm. Besides these also 290 Bergmann in 7.63-mm x 25 Mauser calibre were offered from Switzerland, but the Finns decided not to buy them (probably because yet another new calibre for submachine guns would have complicated ammunition supply). During World War 2 Finnish military issued Bergmann submachine guns with four magazines, spare barrel and magazine loading tool. During Continuation War Bergmann submachine guns were first issued to coastal troops (until captured Soviet submachine gun soon replaced them in that use) and later they were used by homefront troops. In this way they kind of returned home as basically homefront troops, which contained mostly Suojeluskunta members, which were not fit for frontline duty. After World War 2 Suojeluskunta was disbanded and ownership of remaining Bergmann submachine guns were again transferred to Finnish Army - this time for good. Finnish Defence Forces kept Bergmann M/20 warehoused until they were sold to Interarmco in 1960.

Lindelöf submachine gun, Finnish copy of Bergmann:

Finnish Leonard Lindelöf's machine factory got itself license for production of Bergmann submachine gun in 1922. As the name suggests Leonard Lindelöf owned the factory. submachine guns that this factory was to manufacture under license were exact copies of Swiss Bergmann M/20. Lindelöf had grand plans of large-scale mass-production of submachine guns and invested accordingly. Early on the prospects for this factory looked positive as the first order arrived swiftly - Suojeluskunta (Finnish Civil Guard) ordered 200 submachine guns identical to 7.65-mm Bergmann M/20 in December of 1922. But then Lindelöf's factory run into problems - it had promised delivery of these 200 weapons in just 8 months and this proved much too little. Production-wise Bergmann-submachine gun was typical 1st generation submachine gun - complicated weapon with its parts machined from steel. So manufacturing them was slow and demanded large number of tools and machinery. Time needed setting up production had been seriously underestimated and even suspicion of sabotage surfaced. These delivery delays were breach of contract and because of them Suojeluskunta cancelled its order. Heavy hit came when Swiss played Lindelöf out from competition by offering Bergmann SMG with bargain prices to Suojeluskunta in 1923, these bargain priced Bergmann submachine guns filled the needs of Suojeluskunta and lead into situation in which Suojeluskunta no longer had needs to buy more submachine guns for some time. Because of this Lindelöf's lost his only important customer and when first submachine guns made by his factory finally were finished in 1925 the factory had sell them in small quantities to any authorities willing to buy (local level Suojeluskunta organisations, Police, Customs, Coastal Guard, Estonian Police etc...). The factory had about 160 mostly unfinished submachine guns warehoused, but no clients for them.

Year 1930 Lindelöf contacted again Suojeluskunta trying to sell the remaining submachine guns. However Suojeluskunta was loosing interest as the new Suomi submachine gun made Bergmann-design look outdated. Soon after this Lindelöf's factory faced financial difficulties. Year 1932 he contacted again Suojeluskunta, who decided to help the factory by ordering 10 submachine guns, which the factory was to manufacture from its unfinished parts. The factory gave Suojeluskunta 12 already finished submachine guns as a pledge. But once again keeping to the contract proved impossible for the factory - as earlier the delivery was delayed again and again. Suojeluskunta had no other option than cancelling the contract and take possession of the 12 submachine guns earlier given as a pledge. The final nail to coffin for Lindelöf's plans was when Suojeluskunta that same year made decision from that on to buy only Suomi M/31 submachine guns instead of Bergmanns. Lindelöf had acquired the tools and machinery made for production of Bergmann submachine guns, but now had to sell the unfinished parts and tools as junk. Lindelöf version of Bergmann submachine gun when compared to the Swiss one was not such a high quality and its magazines were not interchangeable, but otherwise the weapons were identical. The small amount of Lindelöf made Bergmann submachine guns were used the same way as the Swiss made ones and got experienced exactly the same fate in Finland during World War 2 and after it. The estimated total production of Lindelöf submachine guns was only about 60 or 70. While Lindelöf's factory never again manufactured complete firearms it manufactured parts for some weapons still during World War 2.

 

Suomi submachine gun:

Prototypes:

According Aimo Lahti himself interest for designing submachine gun of his own born because Bergmann submachine gun was so expensive and not very good. Lahti started thinking that he would be able to make a better submachine gun - and he proved to be right. 1st of June 1921 Aimo Lahti was hired as gun-master to Keski-Suomi Regiment and started developing his idea of submachine gun soon afterwards. First prototype he ordered was a miniature of sort in 7.65mm x 17 (Browning aka .32 ACP) calibre, only about 30 cm long and made by blacksmith in Viiala for him. The first prototype was no work of art but it proved that the basic construction that Lahti had designed was a working one.

Year 1922 he ordered the first real sized prototype (M/22), which was build by Machine workshop Leskinen & Kari in Tampere. It was in 7.65mm x 21 (Parabellum) calibre and had the same rate of fire as in later M/26. Lahti got support from commanders of Keski-Suomi Regiment Colonel-Lieutenants W. Hägglund and E. Heinricks, but they did not manage to get any state financing for this development work. Spring of 1923 the prototype was sent to Defence Ministry, but it failed to raise interest. M/22 was not exactly well made or ready for production, but it had plenty of hidden potential.

At June of 1924 Lahti established Konepistooliosakeyhtiö (= Submachine gun Ltd) with some officers of the same regiment. The other shareholders of this new business enterprise were Captain V. Korpela, Lieutenant Y. Koskinen and Lieutenant L. Boyer-Spoof (later changed his sir-name to Poijärvi), the total amount of shares was 150. Lahti got 45, Korpela 45, Koskinen 30 and Boyer-Spoof 30 shares. The new company had a lot of inspiration, but very little finances. Some of business partners even proved to be too inspired - Lieutenant Korpela had to leave the company after trying to sell the submachine gun abroad without permission of other shareholders.

PICTURE: Suomi M/26 submachine gun with its rather eccentric looking 36-round magazine. Notice the fire selector switch on side of the weapon and barrel jacket quick release latch on top of the magazine. (Photo taken in Metsästysmuseo). CLICK THUMBNAIL TO SEE LARGER PIC (40 KB).

7,65 mm Suomi M/26:

Lahti was improving his submachine gun-design all the time making several improvements, which were all patented in Finland as soon as they had been invented and development was starting to look ready for mass-production. Konepistooliosakeyhtiö ordered one hundred submachine guns from Ab Tool Oy and at August of 1924 also Finnish Defence Ministry finally got interested. February of 1925 first batch of 13 submachine guns were inspected by Ordnance Department of Finnish Armed Forces. The weapons worked well, but their magazines only worked with individual weapon to which they had been intended and barrels were already slightly corroded. However, they were accepted even with these small problems. Army ordered additional ten submachine guns in October of 1925 and another 39 in March of 1926 and bought even earlier made prototypes. This proved highly useful since at that time Konepistooliosakeyhtiö and its shareholders were just about broke, so they needed every possible bit of money that they could get. From this production series of about 100 weapons most (over 60) ended up to Finnish Army, but also Suojeluskunta (Finnish Civil Guard) and Frontier Guard bought them in small numbers. Few weapons of this series were delivered abroad as samples (among them 5 to Estonia). Later submachine guns of this production series were named as M/26 to make them easily separated from M/31 Suomi. Suomi M/26 ended up costing only about 2,200 Finnish marks/submachine gun while Bergmann at that time cost usually more than double (4,500 Finnish marks). Arch-shaped 36-round magazines used with Suomi M/26 were unique in that sense, that they were not used in any other weapon. Like later M/31 also M/26 had quick release system, which allowed changing its barrel in matter of seconds. Normally they were issued with spare barrel and tool pouch.

Suomi M/26:

Calibre:

7,65 mm x 21 Parabellum (.30 Luger)

Length:

930 mm

Barrel length:

350 mm

Weight:

4,18 kg

Fire-rate:

600/minute

Magazine:

arch: 36

Abbreviations:

"7,65 kp/26"

Country of origin:

Finland

Prototype:

1924

Production:

About 100 made between 1925 - 1926.

Suomi M/26 never got into real combat use, during World War 2 they were issued troops doing guard duty in home front. During the war they were apparently issued with only two two magazines per weapon - quite likely due to limited number of magazines originally manufactured for them. Year 1959 the remaining 57 Suomi M/26 were sold to Interarmco and shipped abroad year 1960. This was a one of the darkest moments of Finnish weapons history as along the "ordinary" M/26 also all its one of a kind prototypes were sold without understanding their value. Luckily they were not wrecked and ended up to foreign museums and arms collectors.

9 mm Suomi M/31:

PICTURE: Early version of Suomi M/31 submachine gun with 70-round drum magazine. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (76 KB).

PICTURE: Late version of Suomi M/31 submachine gun aka M/31 SJR with 50-round box magazine. Notice muzzle brake in end of barrel. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (76 KB).

Aimo Lahti was not happy with M/26 submachine gun, its feeding process was not as reliable as it should have been and the stock was not robust enough for first grade military weapon. Submachine gun M/26 also shared several design weaknesses of foreign submachine guns like MP-18/I and MP-28/II, which Lahti succeeded fixing while developing submachine gun M/31. He eliminated the excessive room in front of bolt (which had allowed cartridge sometimes to turn sideways causing jam) and the feeding problems disappeared. The quick-release method used for attaching the barrel and barrel jacket to receiver allowed barrel to be quickly replaced if needed. Barrel of the weapon also sported new tilted end, which somewhat decreased tendency of muzzle to climb during shooting. The barrel jacket around the barrel was modified to be structurally more simple and robust. However, the most important change that came with submachine gun M/31 was changing of calibre to 9 mm x 19 (Parabellum), as this new ammunition allowed also new type of magazines to be developed. Lahti designed all these improvements plus new 20 round box magazine and 40 round drum magazine around 1930 - 1931. Finally Finnish Defence Ministry became interested, but there was no yet factory for manufacturing this new submachine gun.

PICTURE: Empty 40-round drum magazine opened. This magazine was designed by Aimo Lahti in year 1932. Fully loaded it weights exactly the same as 70-round drum, but was also much more difficult to load, as bullets had to be placed on their tips when loaded to magazine. When this magazine design proved also somewhat unreliable, it is not surprising that its production ended already in year 1939. Nowadays 40-round drums for Suomi submachine gun are very rare and valuable. CLICK THUMBNAIL TO SEE LARGER PIC (129 KB).

Engineer Oscar Östman, who was leading Tikkakoski Rauta ja Puuteollisuusyhtiö (= Tikkakoski Iron and Wood Industry Ltd) at that time knew Lahti personally and was also very interested about the new submachine gun M/31. Tikkakoski had manufactured weapons parts like rifle and machinegun barrels for Finnish military earlier, so it had also some experience of weapons manufacturing and selling products to Finnish military. Shareholders of Konepistooliosakeyhtiö finally earned from their work when Tikkakoski bought the mass production rights of submachine gun M/31 as its sole manufacturer. This ended the story of Konepistooliosakeyhtiö, which now had served its purpose.

PICTURE: Fully loaded 70-round drum magazine opened. Lid of the magazine in left side of the photo. The actual maximum capacity of this magazine type is 72 rounds, even if Finnish military prefers to call it 70-round magazine. Experiences suggest that there was a reason for this - loading only 70 rounds instead of 72 seems to increase reliability of this magazine model. CLICK THUMBNAIL TO SEE LARGER PIC (57 KB).

While Suomi submachine gun was finally getting recognition it earned, the early magazines (20-round box and 40-round drum), which Lahti had developed in early 1930's proved less than ideal. 20-round box magazines existed in two versions, which actually had maximum capacity of 25 rounds, but if filled to full capacity they didn't work reliably, while when loaded only with 20 rounds they worked rather well. The 20 round magazines were quite small and handy (they weight only some 0,2-kg empty and 0,44-kg when loaded with 20 rounds), but they had too small ammunition capacity and proved too difficult to fill fast, so their production was ended already before year 1939. Production of 20-round magazines was restarted during Winter War, but once Winter War ended the production was stopped again - this time definetely. 40-round drum magazine proved unreliable, but even more difficult problem was with filling it - cartridges had to be inserted in such manner that they stood on tips of the bullets. Smallest mistake would cause the cartridges felling in their side inside the 40-round drum magazine, creating mixed pile with only one solution - drop all cartridges off the magazine and start the whole process of inserting cartridges from the start. The 40-round drum wasn't terribly effective for its weight either, it weight 1,0-kg empty and 1,48 kg full while 70-round drum weight 0,87-kg empty and 1,48-kg when fully loaded. The magazines typically used with Suomi M/31 during World War 2 were 70-round drum and 50-round box. From these two, the 70-round drum magazine became the best known magazine for Suomi submachine gun. Yrjö Koskinen (one of shareholders in Konepistooliosakeyhtiö) designed it without Lahti even knowing about this new magazine type before it was finished. Koskinen's drum magazine proved to be the best magazine available for Suomi M/31 during World War 2 - it was reliable, handy (even if somewhat heavy) and offered excellent firepower. In addition unlike many other drum magazine designs this magazine did not allow cartridges loaded inside it to rattle. Koskinen's 70-round drum magazine entered production in year 1936 and remained in production until late 1944. The 50-round box magazine was Swedish design, which Tikkakoski started manufacturing under license in year 1941. 50-round box magazine was not as good as 70-round drum magazine, but it was easier and cheaper to manufacture. However, the wartime use proved this box magazine to be structurally too delicate (smallest dent in the wrong place could jam it) and impossible to reload anywhere near full capacity without separate loading tool. Because of these reasons production of the 50-round box magazine was stopped in autumn of 1943. Rest of the war only 70-round drum magazines remained in production and became the most common magazine used with Suomi M/31 submachine guns during World War 2. Before and during World War 2 Tikkakoski, who was sole manufacturer of Suomi M/31 in Finland, was also the sole manufacturer for its magazines.

The number of magazines that Finnish military issued with Suomi M/31 during World War 2 varied, but year 1943 this weapon was supposed to be issued with either five 70-round drum magazines or seven 50-round box magazines. The equipment used that Finnish soldiers often used to carry drum magazines of Suomi M/31 during World War 2 was somewhat improvised combination of hooks, straps and/or rope that allowed hanging drum mags to their service belt. There were no purpose-built magazine pouches in Finnish use, so soldiers also used variety of suitable bags for this purpose. These included bread bags, gas mask bags and magazine bags originally made for carrying of 10 Lahti-Saloranta light machinegun magazines. Carrying box made from plywood was developed for 50-round box magazines and manufactured for home front troops (Civil Guard) during Continuation War. Typically only home front troops used these magazine boxes since they would have suited poorly for frontline use, as they were clumsy and made noise (magazines rattled inside them) during movement. Some sources claim that drum-magazines used in Suomi M/31 would be related to ones used in Thompson submachine gun, but this is false information. The only connection was in conceptional level - both Lahti and Koskinen may were likely aware about drum magazine(s) used in Thompson, but its unclear if this even effected to their decision of developing drum-magazines for Suomi M/31 in any way. From technical point of view both L- and C-drums used in Thompson are structurally and mechanics-wise totally different from 40- and 70-round drums used in Suomi M/31.

PICTURE: 50 round box magazine for Suomi M/31 submachine gun. This magazine model was/is generally known as "coffin-magazine" because of its shape. Filling more than 50 rounds to this was magazine was strictly forbidden because that usually results magazine getting jammed. CLICK THUMBNAIL TO SEE LARGER PIC (121 KB).

Magazines Finnish military used with Suomi m/31 submachine guns:

Magazine:

Capacity:

Weight Empty / Full

Manufactured:

Details:

20-round box

25

0.20 kg / 0.44 kg

1931 - 1940

Since 1941 in secondary use

36-round box

36

0.40 kg / 0.85 kg

1954 - 1958

Swedish m/54, Finnish m/55

40-round drum

40

1.00 kg / 1.48 kg

1931 - 1936

Mostly in secondary use

50-round box

50

0.39 kg / 1.02 kg

1940 - 1943

70-round drum

72

0.87 kg / 1.48 kg

1936 - 1944

Most common during WW2

PICTURE: Oops... Even if loading of 70-round drum magazine was much easier than the 40-round drum magazine, it still took only one clumsy move to make already inserted cartridges to overturn. Fixing a pile-up like this is not something that one would like to do in freezing weather or in middle of firefight. CLICK THUMBNAIL TO SEE LARGER PIC (54 KB).

It is not exactly common for small arms to be named after the country in which they are being manufactured, so in that sense this submachine gun getting named Suomi (Finland) was rather exceptional. It seems to be somewhat unclear who came up with the name first, but calling Lahti's submachine gun as Suomi submachine gun (Suomi konepistooli) had spread to Finnish military documents already in year 1925. The first public display of new 9 mm Suomi submachine gun and publicity given by Hakkapeliitta Magazine (magazine of Suojeluskunta aka Finnish Civil Guard) in September of year 1930 made Suomi submachine gun practically a household name both among Finnish military and Suojeluskunta organisation. October of 1931 Finnish Army decided to place its first order of 100 new Suomi submachine guns in 9-mm calibre - this resulted the weapon getting officially named 9 mm submachine gun M/31. Tikkakoski made Suomi submachine gun M/31 available with several options that included front handle, bipod and two alternative designs for selector switch. From these options Finnish Armed Forces ordered the most simple variation and stick with it. Also Finnish Civil Guard (Suojeluskunta) followed suit and decided to acquire the same version of Suomi M/31 that armed forces had already chosen from that on. Other available options of this weapon manufactured by Tikkakoski were sold only with export deals, which were far and few before World War 2, making them very rare.

PICTURE: Cut open Suomi M/31 submachine gun showing structure of the weapon. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (24 KB).

Before World War 2 orders for Suomi M/31 were coming in slowly, by 1934 the now more shortly named Oy Tikkakoski Ab had delivered only 375 Suomi M/31 submachine guns to Finnish Army. When Winter War started the amount of these weapons in use of Finnish Armed Forces was not more than about 4,000 and increasing the production fast proved difficult. Only about 730 were manufactured during this war. Production continued and expanded after Winter War and during Continuation War settled to level of 1,400 - 1,500 weapons per month. It could be noted that equipment delivered with Suomi M/31 were also somewhat exceptional for submachine gun. Most deliveries included spare barrels. The idea was that each of these weapons was equipped with two barrels (original and spare), which both had similar dispersion and point of impact. With barrel quick release this allowed changing barrel even in middle of firefight without needing to adjust sights or loosing any shooting accuracy. Replacing barrel of Suomi M/31 is remarkably easy and fast and obviously designed for soldier in the field to do for his weapon when necessary - both barrel and barrel jacket are locked to weapon with one single simple switch. Also disassembling and re-assembling Suomi M/31 is quite easy. In fact the only remotely difficult part of doing this is re-inserting of recoil spring, which demands certain technique to make sure that the spring does not get bent.

Suomi M/31 "basic version":

Calibre:

9 mm x 19 Parabellum/Luger

Length:

870 mm / 925 mm

Barrel length:

314 mm

Weight:

4,72 kg / 4,9 kg

Fire-rate:

900/minute

Magazine:

boxes: 20, 50, drums: 40, 70 (72)

Abbreviations:

"9,00 kp/31" and "900 KP 31"

Country of origin:

Finland

Prototype:

1931

Production:

Estimated 80,000 manufactured 1931 - 1953.

During the war Finnish soldiers gave grateful feedback, but the feedback also revealed that Suomi submachine gun was not perfect. Tendency for recoil to cause muzzle climb still existed and was seen as largest remaining problem. With sudden spur of cases showing serious barrel corrosion spotted in January 1940 (at the time believed to be result of snow and debris getting to barrel) lead into idea that something had to be done (later on it was proved that the corrosion had been caused by use of wet ammunition). Both 13th Weapons Repair Company and Ordnance Department of Finnish Army designed muzzle brakes for Suomi M/31. After some testing Ordnance Department selected its own version for production. This new muzzle brake was included into all Suomi submachine guns ordered by Finnish Armed Forces after February of 1943. Suomi M/31 ordered by HQ of Home Front Troops (GHQ of Civil Guard) and those made for export were not equipped with muzzle brakes even after this, they remained to be exactly same as the earlier version of M/31. The muzzle brake was 95-mm long and 28-mm thick, so it added some 55-mm to total length of the weapon. Aimo Lahti was not happy about muzzle brake being added to his invention, in fact his opinion was that it only decreased muzzle-velocity and lead to poorer reliability. Letters SJR (from word suujarru = muzzle brake) were soon added to naming of muzzle braked Suomi submachine guns for purposes of spareparts supply. During Continuation War Aimo Lahti designed also cheaper, faster and easier to manufacture version of 9-mm Suomi submachine gun called M/42, but it never got beyond prototype stage.

PICTURE: Suomi M/31 SJR submachine gun. CLICK THUMBNAIL TO SEE LARGER PIC (58 KB).

Bunker version of M/31 Suomi ("Korsu-kp"):

Calibre:

9 mm x 19 Parabellum/Luger

Length:

740 mm

Barrel length:

314 mm

Weight:

4,35 kg

Fire-rate:

900/minute

Magazine:

boxes: 20, 50, drums: 40, 70 (72)

Abbreviations:

"900 kp/31 korsu" and "900 KORSU KP 31"

Country of origin:

Finland

Prototype:

1939

Production:

500 manufactured in 1941.

Summer of 1939 it became clear that submachine gun Finnish Army needed submachine gun, which could be used shooting from vision slits or steel observation cupolas of bunkers. Ordinary Suomi M/31 submachine gun had barrel jacket, which made shooting the weapon from narrow vision slits difficult and also sights and butt structure poorly suited for this use. Ordinary Suomi M/31 submachine gun was also too long to be operated efficiently inside the observation cupolas. So a bunker version with longer and narrower barrel jacket, pistol grip and sights located in left side of the weapon was hurriedly designed. Prototypes were made and tested and the weapon received official approval in September of 1939. But then started Winter War ruining production plans, as resources needed for production were needed elsewhere.

PICTURE: Bunker-version of Suomi-submachine gun. This particular weapon is "mass-produced" version of this weapon - one of the only 500 ever made. Notice the additional sights in side of the barrel jacket. CLICK THUMBNAIL TO SEE LARGER PIC (50 KB).

So, when Winter War started only few prototypes of this submachine gun version existed. Yet Finnish troops managed to get in their hands some Suomi M/31 bunker-submachine guns of one sort already during Winter War. Some barrel jackets of bunker versions had already been manufactured and during Winter War Finnish troops installing them to their ordinary Suomi M/31 submachine guns. The resulting weapon was so long that it could not be really used in observation cupolas of bunkers, but at allowed aimed fire through narrow vision slits. During Continuation War situation of bunker submachine guns improved as in January 1941 as part of order of 9,500 Suomi M/31 submachine guns also 500 bunker-version submachine guns were ordered. The early models of bunker submachine guns made for tests had 385-mm barrel jacket, special frame and wooden grips that came in two parts. In mass-production bunker-submachine gun version barrel jacket was 435 mm long, frame and grip structure resembled the ones used in ordinary version and sights were sturdier. Bunker versions of Suomi M/31 remained warehoused to depots of those areas of Finland that had fortifications until 1970's. After this some were given to museums and most went through modification process that made them ordinary Suomi M/31 submachine guns.

Tank version of M/31 Suomi:

This was a special version made for Vickers 6-ton tank (later known as T-26E after equipping the turret with captured 45-mm Soviet tank gun and DT machinegun after Winter War). Those tanks had a firing port specially designed for this submachine gun in their front hull. If crew needed, they could easily remove the weapon from its firing port - when needed allowing it to be equipped with normal barrel jacket and to be used like a normal submachine gun. The tank version had a special barrel jacket designed to fit into firing port (permanently attached to the firing port) and pistol grip. While this weapon with its pistol grip resembled the bunker-submachine gun version, it has normal Suomi M/31 rear sight. When used in the firing port the submachine gun was equipped with simple optical sight. Only few dozen tank-version of Suomi M/31 were made before Winter War and those were the only ones ever made. Soviet DT machineguns were captured in large numbers already during Winter War and proved to be more effective in armoured vehicle use than tank-submachine guns. So, the tank-version of Suomi M/31 never saw mass-production. The total production was probably only about 40 weapons, from which 31 remained in summer of 1940. While the number was small they were intended only for 32 Vickers 6-ton tanks, from which 24 were modified as T-26E. These rare weapons remained included to official Finnish Defence Forces weaponry until 1980's (long after the T-26E tanks, in which they had been used, were all gone). This may have happened simply because nobody remembered to officially inform them not being needed anymore.

Experiences of Finnish Army:

Suomi M/31 submachine gun proved to be excellent submachine gun: It had superb firepower, excellent accuracy, good muzzle-velocity and outstanding reliability. Only minus for its users was its weight. When introduced in early 1930's Finnish Army integrated Suomi M/31 submachine gun to existing organisation of infantry. At that time Finnish rifle platoons each had four squads - two light machinegun squads and two rifle squads. Submachine guns were issued to rifle squads with one weapon per squad. While some sources suggest that due to this Suomi M/31 would have early on been intended to serve as kind of a replacement for light machinegun, this seems be inaccurate. Military manuals from 1930's suggest that main idea was to boost short-range firepower of rifle squad, which in tactical concept of "fire and movement" were mainly responsible of movement, while light machinegun squads provided fire support for this. Still, in this tactical concept submachine gun played important role and was more of a squad weapon, than individual one. That part of the tactical concept proved to be a poor idea, but when the correct role for submachine gun was understood Suomi m/31 proved huge success. It proved remarkably effective once used as individual weapons issued to most capable soldiers. It gave these individual capable soldiers excellent short-range firepower in relatively compact form - light machineguns were notably large and heavy compared to it. Suomi submachine gun was unusually accurate weapon as a submachine gun and had longer range than most other submachine guns of its time. This was thanks to quite good ergonomics, rather long barrel (when compared to other submachine guns of that time), small recoil, powerfully loaded ammunition and quite a good sights. Rear sight is fully adjustable and has rather optimistically settings up to 500 metres, while front sight is drift adjustable. In Finnish forests effective shooting range of Suomi M/31 typically proved long enough and thanks to 70-round drums and fast rate-of-fire Suomi M/31 was able to spray more lead into air faster than grand majority of other automatic weapons of that time. Hence it is no suprise that Suomi M/31 become favoured weapon among Finnish troops as it proved to be ideal weapon for the best soldiers to make their most. Summer of 1940 armament of rifle squads belonging to Finnish infantry regiments got re-planned, now every rifle squad got both light machinegun (as squad support weapon) and submachine gun for short-range firepower. The number of submachine guns needed for making this a reality was lagging behind and 1941 many Finnish infantry regiments were still unable to equip all their rifle squads with submachine gun. Autumn of 1942 Finnish Armed forces finally had all the submachine guns needed for this purpose, but Suomi M/31 had proved so effective that at that point committee led by General Heinricks went ahead and decided to recommend adding second submachine gun to all rifle squads as soon as possible. By end of 1943 enough Suomi M/31 submachine guns had been manufactured for this new table of organisation and equipment to be fulfilled, so then decision about providing third submachine gun for each rifle squad was made, but this didn't materialise in large scale before Continuation War ended resulted halting of the Finnish weapons production. Early June 1944 number of Suomi M/31 submachine guns in use of Finnish Armed Forces had peaked to bit over 52,600.

PICTURE: Suomi M/31 has selector switch, which goes though front part of trigger guard. This selector switch has three settings (from front to back): automatic fire, semiautomatic fire and safe. The photo on the left shows the switch with setting "safe" while the one on the right shows it with setting "full auto". CLICK THUMBNAIL TO SEE LARGER PIC (50 KB).

Suomi M/31 submachine guns delivered to Finnish Army between 1939 - 1944:

year

production

1939

1172

1940

3600

1941

11475

1942

13067

1943

15933

1944

11600

Total

56847

Notice: Those made for HQ of Home Front Troops (pre-war Finnish Civil Guard HQ), ordered by Interior Ministry or exported abroad are not included to these numbers.

Losses in battle, broken weapons and weapons hidden to weapons caches dropped number of Suomi submachine guns to just little bit over 40,100 by 5th of October 1944. Repairs and weapons returned from weapons caches started slowly raising the number. August of 1951 Finnish Armed Forces had about 50,100 Suomi M/31 submachine guns and about 300 bunker-version of Suomi submachine guns. Some 27,800 of these remaining Suomi M/31 were the muzzle-braked equipped (SJR) version. Year 1953 Finnish Defence Ministry bought unfinished materials from Tikkakoski factory, these included 3,517 Suomi M/31 (that had not been previously finished). Summer of 1957 some 53,600 remained in ownership of Finnish Armed Forces. In mid 1950's new Swedish designed 36-round box magazine (which the Swedes had originally introduced for Carl Gustav m/45 submachine gun) was first bought from Sweden and soon introduced to production under license in Finland. In 1950's and 1960's these new 36-round magazines replaced old 20-round, 40-round and 50-round magazines, which were mostly scrapped. The new Swedish designed 36-round magazine proved excellent - easy to fill with cartridges, handy and reliable. From 1960's to 1990's old 70-round drums and new 36-round box magazines were the magazine types used with Suomi submachine guns. Assault rifles replaced Suomi M/31 in most Finnish military units in 1960's and 1970's, but large number still remained warehoused for reserves of Finnish Defence Forces until late 1990's. In 1990's AKM-type assault rifles bought from Germany and China finally replaced by then very old-fashioned Suomi M/31 submachine gun. Even if it isn't no longer part of weaponry used by Finnish military some Suomi M/31 still remain warehoused for the Finnish reserve police. Even today Suomi submachine gun had legendary reputation among Finns. Few years ago in a poll Finns voted Suomi submachine gun as the second most important Finnish invention of 20th century.

PICTURE: Finnish made 36-round box magazine used in Suomi M/31 and submachine gun M/44. In Finland Lapua was sole manufacturer of these magazines, which were also known as M/55. The Swedish version (as known as M/54) manufactured by AB Linde Kvarnmaskiner for Finland lacks the carrying loop, which was added to Lapua made version. CLICK THUMBNAIL TO SEE LARGER PIC (36 KB).

Export deals of Suomi submachine guns before World War 2:

Before World War 2 orders of Finnish military were so small that capacity for export production existed, so Tikkakoski offered Suomi submachine gun foreign customers. Starting from 1931 several introduction tours were done by Aimo Lahti and Tikkakoski representatives to other European countries (mainly to Germany and Baltic countries), but projects for sales to more far away countries existed also. However gaining good export deals failed. Only somewhat large deal following from these efforts was for Estonian Armed Forces, which bought 485 Suomi M/31 submachine guns, which were delivered in September of 1938. Tikkakoski developed two versions (both called M/33) of Suomi submachine gun for Persia. These two M/33 prototypes had upwards pointing box-magazine on top of the weapon and bipod below barrel. The main difference between two M/33 prototype versions was pistol grip, which one version had and another didn't. But due to changes in Persian political situation (coup) the actual order for M/33 from Persia never came. Smaller deals were also done with customers like Polish State Police (20 Suomi submachine guns delivered in 1933), but the success had to wait until World War 2. According what is known small numbers of Suomi submachine guns found their way to Chaco War (Bolivia vs. Paraguay 1932 - 1935) and to Spanish Civil War (1936 - 1939). Year 1940 French military had about 300 Suomi M/31 submachine guns, grand majority of these belonged to weapons confiscated from remains of Spanish Republican Army units, which had headed to France in end of Spanish Civil War.

Exports of Suomi M/31 submachine guns during World War 2:

During Interim Peace and Continuation War Tikkakoski also exported Suomi submachine guns abroad. Many of largest deals were made to insure getting vital machinery or raw materials in exchange. Export permits given in that time included:

Export Permits during Interim Peace and Continuation War.

14th of August 1940

220

to Sweden

14th of August 1940

5000

to Bulgaria, almost certainly no actual deal

31st of October 1940

50

to Sweden

16th of January 1941

26

to Denmark

18th of December 1941

5

to Bulgaria

20th of January 1942

40

to Sweden

12th of March 1942

1742

to Germany

20th of April 1942

10

to Sweden

26th of June 1942

1100

to Germany

26th of June 1942

500

to Bulgaria, probably no actual deal

26th of June 1942

100

to Sweden

22nd of October 1942

500

to Croatia

26th of November 1942

100

to Switzerland

29th of April 1943

7

to Denmark

20th of May 1943

5000

to Switzerland, all not delivered?

1st of July 1943

750

to Croatia, almost certainly no actual deal made

5th of August 1943

200

to Germany*

Total

15350

* Ordered by Privatkanzlei des Führers, Hitlers private chancellery. The weapons of this deal probably went to Waffen-SS.

(Source of this chart: Sotilaskäsiaseet Suomessa 1918 - 1988, part 2, page 267.)

In addition Romania wanted to buy 5,000 Suomi M/31 submachine guns in year 1942, but the deal didn't happen as orders of Finnish military were a priority. For the same reason many of the planned export deals listed above could not be filled. In addition July of 1942 Finland donated 120 new Suomi M/31 submachine guns to German AOK Norwegen located in Finnish Lapland. Large number of the submachine guns sold to Germany seems to have ended up to SS and Waffen-SS, as they were typically issued more mixed weaponry than Wehrmacht (German Army). Both 50-round box magazines and 70-round drum magazines seems to have been exported with the weapons.

License production and Finnish made Suomi M/31 submachine guns in other countries:

Swedish versions:

  • M/37: Version manufactured by Husqvarna factory under license. Chambered to same 9 mm x 20 Browning Long cartridge as Swedish Army standard sidearms FN M/03 and Husqvarna M/07 of that time. 56-round box magazine was used with this weapon. Only small number manufactured before Swedes decided to favour 9 m x 19 cartridge.
  • M/37-39: Version manufactured by Husqvarna under license. Chambered to 9 mm x 19 Parabellum/Luger cartridge. Replacing earlier M/37 in production it was manufactured from 1939 to mid 1940's. The Swedes also exported this version to Norway, Denmark, Indonesia and Egypt. When compared to Finnish Suomi M/31 the Husqvarna M/37-39 has very different kind of stock with low-gradient pistol grip-part, shorter (23.1-cm) barrel, shorter barrel jacket and simplified sights. Length of the whole weapon was 77 cm and it weight some 3.9 kg empty (or 4.9-kg with fully loaded magazine). The Swedes used these with the same 50-round box magazines that also the Finns manufactured during World War 2.
  • M/37-39F: Original Suomi M/31 submachine gun manufactured by Tikkakoski imported from Finland. All of these were identical to early version of Suomi M/31 used by Finnish military, in other words: they did not have the muzzle brake. Swedish military used these first with 50-round and later also with 36-round box magazines (similar to the ones used in Finland and in case of 36-round magazine also in Swedish Carl Gustav M/45 submachine gun).
  • Danish versions:

  • M/41: Small number of Finnish Suomi M/31 submachine guns had been exported to Denmark already before World War 2. During World War 2 Madsen and Hovea started manufacturing their copy of Suomi submachine gun called M/41. The Danish production went (at least originally) to Danish Army, which the Germans did not disband and disarm until October of 1943. By that time at least 1,400 submachine guns M/41 had been manufactured. After disarming of Danish Army the weapons seem to have went to German use and they may have issued some to their local collaborators. The main differences of original Finnish M/31 and its Danish made copy are in neck area of the weapons stock and in its front sight (M/41 had protective blades in sides of the front sight).
  • Swiss versions:

  • Mp.43: November of 1942 the Swiss signed contract purchasing 5,000 Mp.43 submachine guns, as they called Suomi M/31, made by Tikkakoski and imported to Switzerland from Finland. It seems that The Swiss did not get quite all of these, because quite naturally deliveries to Finnish military were priority for Tikkakoski. All of these were similar to early model of Suomi M/31 used by Finnish military, in other words - the version without the muzzle brake.
  • Mp.43-44: However the contract signed in November 1942 included also a manufacturing license, which the Swiss put to good use. Hispano-Suiza factory utilised it by manufacturing estimated 22,500 submachine guns Mp.43-44 (as this version is known in Switzerland). When compared to Mp.43 the Swiss Mp.43-44 had a simplified rear sight, which had L-shaped head. This L-shaped head in rear sight could be switched to two positions - one set for 100 meters and another for 200 meters. The barrel length of M/43-44 was about the same as in Finnish M/41 and also other dimensions of this version seem very similar to non muzzle brake equipped version of Finnish M/31.
  • Soviet versions:

  • KF-42: During Continuation War a small number Suomi submachine gun M/31 copies in 7.62 mm x 25 calibre were manufactured in Leningrad. The Soviets called this unlicensed copy KF-42 (Karelo-Finskij 42).
  • PICTURE: Swiss Mp.43-44 submachine gun with 50-round box magazine. This was the de facto standard magazine type, which Tikkakoski delivered with the Suomi M/31 submachine guns, that it exported during World War 2. Notice differences in front part of the barrel jacket, if compared to Finnish M/31. (Photo provided by "Gerd Haflinger"). CLICK THUMBNAIL TO SEE LARGER PIC (91 KB).

    Unlike some sources have claimed Finland never acquired any of the license-made Suomi submachine gun versions and none of them saw any use with Finnish military. Only possible exception to this rule might be (likely very small number) of Husqvarna M/37-39 Swedish volunteer unit (SFK) might have brought among its weaponry to Finland during Winter War. As SFK left its weaponry to Finnish military after that war few M/37-39 might have seen Finnish use during Continuation War. At least some of the weapons delivered to Croatia (and possibly Bulgaria) seem to have ended to German hands during the war.

    Writer's personal experiences concerning shooting Suomi M/31 submachine gun: As to be expected, the first impression tends to be how surprisingly heavy this weapon is - due to the extremely robust structure with milled steel parts. Especially the version with muzzle brake is also quite muzzle-heavy. Due to these reasons recoil is minimal. The muzzle climb still exists while shooting on full-auto mode, but considering the high rate of fire it is yet easily manageable and therefore the weapon is easy to control. Accuracy is remarkable to submachine gun firing 9 mm x 19 cartridge - in semiauto mode hitting man size target with each shot from distance of 150 meters is normal. From 50 meters keeping simultaneously four falling-plate type targets down until running out ammunition proved easy. Hitting all four targets with one long burst proved not too difficult either. Sight are simple but effective, aiming proved fast and simple. Triggers feel seem to be relatively heavy, but they are two-stage and the "step" is quite obvious. Old magazines are weakest part of the design - while 70-round drum magazines tend to be extremely reliable, they are difficult to fill with ammunition. 50-round box magazines are difficult to fill with ammunition without a proper tool, but once proper tool and technique are used, are not too difficult. Obviously 36-round box magazine is both easy to fill and use. Typically just about any individual magazine will work in any individual weapon - but there are exceptions to this rule. Reliability seems to be on par with the reputation. Shortly said - this is one of the few World War 2 era small arms, which I would not mind possibly using as a combat weapon even today.


    SUGGESTED LINKS FOR MORE INFO:

    Suomi SMG in Gunwriters More info about Suomi SMG


    SOURCES:

    Markku Palokangas: Sotilaskäsiaseet Suomessa 1918 - 1988 osat 1 - 3 (= Military Small Arms in Finland 1918 - 1988 parts 1 - 3).

    Timo Hyytinen: Arma Fennica 2, sotilasaseet (Arma Fennica 2, military weapons).

    Markku Palokangas and Maire Vaajakallio: Aimo Lahti, asesuunnittelun suuri suomalainen (= Aimo Lahti, the great Finn of weapons designing).

    Timo Hyytiäinen and Harri Hyytinen: Suomi-konepistoolin tarina.

    Thomas B. Nelson: The World's Submachine guns (Machinepistols)

    Thomas B. Nelson and Hans B. Lockhoven: The World's Submachine guns (Machinepistols), Volume I

    Jan Kronlund: Suomen Puolustuslaitos 1918 - 1939 (= Finnish Defence Department 1918 - 1939).

    Clement Bosson: Die Waffen der Schweizer Soldaten.

    Ernst Hostettler: Hand- und faustfeurerwaffen der Schweizer Armee.

    Article: Saksalainen konepistooli 1918-1945 in Ase magazine vol. 2/87.

    Article: Parabellumin rumpulipas by Matti Ingman in Ase-lehti magazine vol. 1/90.

    Article: Suomi-konepistoolin kehitys by Markku Palokangas in Ase magazine vol. 5/1985.

    Article: Miten suomi-konepistoolin lippaita kannettiin talvi- ja jatkosodassa by Esko O. Toivonen in Ase-lehti magazine vol. 1/99.

    Article: Konepistooli "Suomi" by Mika Vuolle in Kaliberi magazine vol. 7/2004.

    Military manual: Jalkaväen pikatuliaseiden käyttöopas (1941).

    Military manual: Konepistooli "Suomi" by P. Huhtala (1935).

    Military publication: Taisteluvälinevarustuksen nimikeluettelot.

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

    Special thanks to Metsästysmuseo (Hunting Museum of Finland, Riihimäki).


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