WEAPONS FINNISH ARMY ALMOST HAD IN WORLD WAR 2, PART 4

Artillery Weapons of All Kind

 

 

20 ItK/L-43

(20 mm anti-aircraft gun model 1943)

PICTURE: 20 ItK/43 anti-aircraft gun protype. Unfortunately there seems to be some parts missing. (Photo taken in Ilmatorjuntamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (150 KB).

This was the last version of 20-mm automatic cannons designed by Aimo Lahti before and during World War 2 and also the last recoil-action weapon that he ever designed. In usual manner he designed it for Valtion Kivääritehdas (VKT, State Rifle Factory), but since VKT already had its hands full with weapons repairs and other projects, the actual protototype was manufactured by much smaller Finnish company Mikro Oy, which was better known as tool manufacturer. Due to their their ever increasing speed during Continuation War fast low-flying aircraft were starting to become difficult targets for existing 20-mm anti-aircraft guns, which were aimed with hand wheels. Following example of previous 7.62 ItKk/31 VKT and 7.62 ItK/31-40 VKT anti-aircraft machineguns Aimo Lahti tried to design twin-barrel 20-mm anti-aircraft gun, which a gunner would hold with his hands for aiming. The gun was belt-fed with fixed drum magazines used for holding the ammunition belts and had maximum rate of fire 2 x 450 shots/minute. Makro Oy built the prototype in 1943 and it was test-fired, but proved problematic. Three versions of gun carriage were tested with this prototype, but all of them proved less unsuccessful. Ultimately the project was cancelled, probably due to lack of free development and production capacity combined with Finnish Army stopping development at end of Continuation War. However it seems also quite possible that the unsuccessful gun carriage designs with recoil of two 20-mm cannons may have proved too difficult to handle. Nowadays the only existing prototype can be found at Ilmatorjuntamuseo (Anti-aircraft Museum) in Tuusula.

PICTURE: View from customer end of 20 ItK/43 anti-aircraft gun protype. Blue rope is not part of the original design. :-) Notice the flash hiders. (Photo taken in Ilmatorjuntamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (92 KB).

Finnish development of light antiaicraft-guns basically ended with shutdown of weapons development in year 1945 and forced retirement of Aimo Lahti in 1947. World War 2 era 20-mm anti-aircraft guns like 20 ItK/40 VKT did a very long post-war career in Finland until finally slowly replaced with Soviet ZU-23-2 introduced to Finnish military use as 23 ItK 61 (23 mm anti-aircraft gun model 1961), which has remained in use until this day.

 

57/55 J

(57 mm coastal gun with 55 caliber barrel, model Jokinen)

PICTURE: 57/55 J coastal gun. The gun shield is missing, the gun shield design used in these guns was similar to one used with 57/58 Hotchkiss. (Photo taken on Kuivasaari Island). CLICK THUMBNAIL TO SEE LARGER PIC (196 KB).

Calibre:

57 mm x 409 R (fixed ammunition) (*)

Barrel length:

315.1 cm aka L/55.4

Weight in action:

955 kg (gun with gun shield and gun carriage)

Rate of fire:

? shots/minute (maximum)

Muzzle velocity:

900 m/sec / 800 m/sec / 630 - 660 m/sec (**)

Traverse:

360 degrees

Elevation:

- 10 degrees, + 32 degrees

Max. range:

12.8 km / 9.0 km (***)

Ammunition weight:

? kg (HE)

Ammunition types:

HE, APHE, SAPHE, shrapnel

Country of origin:

Finland

(*) Originally this gun was designed to use more powerful ammunition, but ultimately ended up with 57 mm x 410 R.

(**) Original intended muzzle velocity around 900 meters per second, this far first reduced to 800 meters per second and ultimately the guns were issued with 57 mm x 409 R ammunition which had muzzle velocity of only about 630 - 660 meters second.

(***) Maximum range was 12.8 kilometers with originally intended (900 m/sec) ammunition, while ultimately used ammunition had maximum range of only 9 kilometers.

Finnish use: 57-mm coastal gun designed by Lieutenant Colonel Jokinen for Finnish Navy during World War 2. Prototype built in year 1941. Due to limited production capability of Finnish industry manufacturing of the first and only production series of 10 guns were not completed until after the war.

During Continuation War Operative Department of Finnish Navy Headquarters came to conclusion that more and better light coastal guns were required to supplement the existing already aging guns. Therefore it ordered development of locally designed 57-mm coastal gun, which was to use more powerful ammunition than guns already existing in inventory. This new guns was also to have proper optical sights and its aiming system was to designed as such that the same gun crew member would not take care of both aiming the gun and firing it, since this had caused problems shooting-accuracy wise with existing guns. The duty of designing the gun was placed on Engineer Lieutenant Colonel Antero Albert Jokinen, who had made a long career as artillery engineer in Navy Headquarters. He took it has personal duty to develop the gun and did the work much very much on his own. The resulting gun shows that in his ambition of trying to develop a perfect gun he failed to understand the very limited production capabilities of Finnish industry.

Jokinen's gun was based to existing 57-mm Hotchkiss and Nordenfelt coastal guns. As normal the gun designed by Jokinen was fixed coastal gun placed on pedestal mount. It had rather large gun shield and cylinder of recoil system containing hydraulic buffer and spring recuperator placed under the gun barrel. The gun had breech system with vertical sliding breech block. It had semi-automatic mechanism, which after firing shot extracted cartridge case, armed the firing mechanism and left the breech system open for inserting the next round. Aiming of the gun was done by using hand wheels.

Prototype of the gun was built by Helsinki Naval Station (Helsingin Laivastoasema) and completed in year 1941. Navy HQ made order of 50 guns to State Artillery Factory (Valtion Tykkitehdas = VTT) in winter of 1941- 1942. But since State Artillery Factory was already over-burdened by its other duties and had no free manufacturing capacity for making them, this order was never completed. From this order only 10 gun barrels and gun cradles were ever manufactured and even they were not delivered until around 1944 - 1945. During test-firing also half-automatic mechanism was found to have durability issues. As if this would not have been enough, the propellant charge that Jokinen had intended to be used in the ammunition proved highly problematic. The muzzle velocity that had intended for its ammunition was 900 meters/second, which was notably more than in previous 57-mm coastal guns, but this created excessive pressure and would have resulted very short service life for gun barrels. Hence Jokinen reduced the muzzle velocity to 800 m/sec, but ultimately these guns were issued with the same 57 mm x 410 R ammunition, that was already in use with other 57-mm coastal guns. So, in the end due to ammunition the muzzle velocity of this gun was in quite similar level as with 57-mm Nordenfelt and Hotchkiss.

Optical sights used with these guns were manufactured by Defense Department's Optical Facility (Puoluslaitoksen Optillinen Laitos) during Continuation War. They were simple box-shaped 5 x 23 monocular gun sights. The same guns were designed to be used also in other light coastal guns, but no information exists about their how many were manufactured or how widely they were issued.

When 57/48 No guns were declared obsolete and removed from use in 1950's, Finnish coastal artillery found itself having shortage of light coastal guns. Since 76-mm guns had been reserved for possible wartime use, they could not be issued. In that difficult situation coastal artillery was forced to introduce or re-introduce to its use some light coastal guns which it had already declared obsolete earlier. Along these also 11 guns 57/55 J, for which the main parts already existed, got official approval. Before this the only actual use that they had seen, had been with few of their gun barrels serving as smaller caliber practice guns with super-heavy 305/52 O guns. Existing 11 guns were rebuilt as complete guns in late 1950's - early 1960's, but did not serve beyond 1965 - 1966.

 

75 K/44

(75 mm cannon model 1944)

PICTURE: 75 K/44 anti-tank gun protype - and yes, this gun really is that low. (Photo provided by Perttu and taken in Panssarimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (122 KB).

Calibre:

75 mm x 714 R (*)

Length:

467 cm (while in transport)

Barrel length:

466.7-cm aka L/62.2 (early) / 418 cm aka L/55.7 (late)

Weight in action:

1350 kg

Rate of fire:

?/min

Muzzle velocity:

? - 1146 m/sec

Magazine:

None

Traverse:

50 degrees

Elevation:

- 6 degrees, + 11 degrees

Max. range:

? m (indirect fire) / ? m (direct fire)

Width:

160 cm

Height:

110 cm

Country of origin:

Finland

Ammunition types:

APHE (Pzgr.39 & Pzgr. 39 AL) 6800 g projectile 903 m/s (**)

APCR-T (Pzgr.40) 4100 g projectile 1146 m/sec (**)

HEAT-T (Pz Patr. 39 HL/B) 4600 g projectile ? m/sec

HE (Spr. Gr. 34) 5750 g projectile ? m/sec

(*) First prototype in 57 mm x 510 R caliber, later prototype in 75 mm x 714 R.

(**) Muzzle velocities test results with late (L 55.7) barrel.

This was a first Finnish-designed antitank-gun ever. Before World War 2 Finland had acquired manufacturing license for producing weapons designed by Bofors in Sweden. As a result two Finnish manufacturers, Valtion Tykkitehdas (VTT, State Artillery Factory) and Tampella manufactured Bofors-designed 37 PstK/36 antitank-gun in 1939 - 1941. While 37 PstK/36 had been a good antitank-gun by year 1939 standard, due to armour protection of new tanks developing heavier and heavier this antitank-gun was no longer effective against them. The other two common antitank-guns found in Finnish inventory at that time, German 37 PstK/40 and captured 45-mm Soviet antitank-guns, were not much better. Hence with apperance of T-34 and Klim Voroshilov tanks Finnish Army found itself without any antitank-gun effective against these new tanks.

Structurally this antitank-design was quite unconventional with the idea about gun in which the gun barrel would on same level as the axle originating from main engineer of Tampella weapons production - Hans Otto Donner. This antitank-gun development became also Tampella's first own development project of antitank-gun. First drawings about this new antitank-gun concept were made in April of 1942. While Donner had come up the basic concept actual development work was lead by engineer Erik Fabritius. The basic concept for this gun was indeed quite unconventional with intention of making the gun as low as possible to spotting as difficult as possible for the enemy. The gun barrel and barrel jacket around it would both through hole in the axle. As a result the gun was very low, but also its barrel was placed much lower than in conventional antitank-guns, which later proved problematic. Axle was equipped with pneumatic tire in each end and split trail gun carridge with trail beams, which could be folded on top of the gun for transport. Gun barrel was very narrow and long for the purpose of gaining as much muzzle velocity for the projectiles from the propellant as possible. Gun barrel was also equipped with long removable muzzle brake designed to reduce recoil. Breech mechanism was with vertical sliding breech block as typical to antitank-guns of the era and semiautomatic in that after firing a shot it automatically extraced cartridge case and cocked its mechanisms ready for the next shot. Recoil system contained two hydraulic buffers and spring recuperator. At least in theory the structucal design was expected to be capable easily handling considerable amount of recoil energy and cause reduced muzzle climb in recoil, therefore allowing faster follow-up shots.

Early on the gun was designed to fire new also Tampella-designed 57 mm x 510 R round. Cartridge case for this new round had been developed by simply adding additional section to existing 76.2 mm x 385R cartridge case. This new section changed caliber to 57-mm and changed the cartridge case as bottle-neck configuration. With this new round the estimated muzzle velocity for 2.4-kg APHE shell was exceeding 1,000 meters/second.

First thing to be build was a wooden full-size mockup gun, which was exhibited to General Nenonen (Inspector of Artillery) and the development project got his approval. Tampella named the actual 57-mm caliber prototype as 57/76 PstK, but the actual gun was not apparently completed until December of 1943. When its barrel was tested separately in Field Artillery Testing Centre in Niinisalo at summer of 1943, the muzzle velocity of 2.4-kg projectile was measured as being about 1,100 meters/second and capable penetrating 150-mm armour plate with 65-degree point of impact. This has to considered excellent achievement considering that the projectile used for testing was apparently simple armour piercing type without tungsten core, however the quality of steel plate and actual shooting distance are unknown.

While 57 mm x 510 R ammunition had showed excellent performance, for obvious reasons Finnish Army was less than exited about waiting development of this ammunition and setting dedicated production for it. However this was not the only reason why Finnish Army was sceptical when it came to Tampella's 76 mm x 510 R round, Colonel Raatikainen was leading Ordnance Department at Finnish Armed Forces GHQ noted that Tampella had pushed ballistics of its own ammunition to its maximum limit which would cause issues with gunpowder.While 57/76 PstK (57/76 mm antitank-gun) prototype was now complete for testing, Finnish Army decided to prefer the gun to be re-designed for 75 mm x 714 R ammunition, which was readily available due to already being used with 75 PstK/40 antitank-guns. The decision caused some debate in between Finnish Army and Tampella until Tampella agreed to re-design the gun for this 75-mm ammunition type in January of 1944. Tampella didn't like selection of ammunition available with 75 mm x 714 R and considered it less effective than its own development. Due to this change the 75-mm version was re-named in February of 1944 as 75 K/44 (75 mm cannon model 1944). According plans made at that time, once development was continued, the first manufacturing batch of this antitank-gun was intended to be 150 guns.

The process of building the first 75 K/44 prototype went swiftly and resulted the gun being test-fired the first time in 16th of March 1944. Due to its notably longer barrel (466.7-cm vs. 345-cm) in these firing tests 75 K/44 proved ballistics-wise notably much more effective than 75 PstK/40, which at the time was most powerful antitank-gun in Finnish inventory. Muzzle velocities of these two guns with 75 pshekrv rj 22/27-ps (German PzGr 39) APHE-round:

While the test-results were ballistics-wise impressive, they also revealed that the prototype while a complete gun, was still in dire need of further development and could not yet be allowed to enter production. The breech mechanism and firing systems had serious problems which far too often resulted the gun either not firing or failing to properly eject the used cartridge case. In combat siuations either problem could have easily resulted the gun getting destroyed and crew killed.Ultimately neither of these issues would be completely solved and continued to haunt the design to the end.

PICTURE: Another view of 75 K/44 showing the breech system of this unusual gun. Notice how the gun barrel goes through axle of the gun. (Photo provided by Perttu and taken in Panssarimuseo). CLICK THUMBNAIL TO SEE LARGER PIC (256 KB).

75 K/44 prototype had been equipped with new very low Tampella-designed and manufactured gun shield designed to provide protection against rifle-caliber armour-piercing bullets. Due to size and shape of the gun shield the gun sight was placed just above the gun shield, but this appears to have been just temporary solution, since location of the gun sight placed the gunner in extreme danger during recoil movement of the gun. Folding trail beams were added to the prototype in May of 1944 and experiments concerning towing the gun with horses was experimented that spring. The conclusions of these tests were that while two horses were enough for towing the gun on road, team of four horses was needed for proper off-road mobility. The project was now going slow since Tampella was having problems with it and there was no decision about what kind of gun sight it was intended to use.

Apparently the Soviet offensive which started in Carelian Isthmus 9th of June 1944 and broke through Finnish main defensive line the next day proved to be the wakeup call, which set the wheels turning once again. 12th of June 1944 Finnish Army and Tampella had a conference in city of Tampere. The long trench-war in Finnish - Soviet front had ended and now Finnish Army needed all modern antitank-guns that it could with preferred delivery date being yesterday. Existing 75 K/44 prototype was to completed in such condition that it could be towed and shot, while smaller improvements could be left at later date. Tampella's estimate was the production could have started five months after arrival of gun barrel materials. But before getting to production the company would need new machinery used for rifling the barrels. While the gun barrel used in 75 K/44 prototype had shown impresive ballistics it also made towing the gun difficult, so Finnish Army decided to rather have somewhat shorter barrel, which would make the gun somewhat more handy. Hence the barrel length was to be reduced from 466.7-cm (L/62.2) to 422-cm (L/56). Besides team of four horses, the gun had to be able to be towed by by hand, with truck or towing tractor. Gun sight was to be developed from telescopic rifle sight and hole for both this telescopic sight and collimator sight was to be made in gun shield.

The prototype was test-fired again in 24th - 25th of July 1944 and this time hull of destroyed KV-1 was used as testing target. As to be expected the gun quite proved capable penetrating both front and side hull, but all through test firing there were problems with small parts breaking or falling off from the gun. As before the gun had also problems with ejecting of used cartridge cases. And as if these had not been enough negative elevation allowed by the structural design proved to be too small, during durability tests trails of gun carriage started to bent, front section of rifling got burned and during towing excersise with team of four horses proved to have issues. The prototype had obviously been anything but ready for this and due to its poor performance the officers that had observed the tests now came up with plethora of changes in a meeting held after these tests.

For purpose of preparing to mass-production Tampella ordered 105 barrel blanks from Krupp in June of 1944, but the industrial capacity of the Germany was no longer what it had used to been. Krupp offered to deliver half of the barrel blanks in April of 1945 while the other half would not have been delivered until July of 1945. Ultimately this proved to be the final nail to coffin of this project. Finland signed cease-fire treaty with Soviet Union in September of 1944 and this ended all deliveries from Germany. Now Finland had little need for additional antitank-guns and the following peace treaty would force halting of Finnish weapons development. The prototype was anything but ready and still had variety of serious issues, which would have be solved if there would be any hope of actually developing a fully functioning reliable antitank-gun. The basic gun design also caused certain handicaps, which now provided good reasons for suspecting the whole concept. The gun was difficult to tow, the telescopic sight placed higher than barrel of the gun might cause accidentally shooting to obstacle not visible through gun sight and due to its structural design the gun could not be used in dug-in gun positions. Hence while it had slightly better ballistics, the resulting gun was considered impractical.

In the end of this project also money-problem appeared. While military had never placed any order for mass-production of this gun Tampella had started making preparations for that that and due to this had spent considerable sum of money for the purpose. Tampella had already started manufacturing parts for the first batch of 50 guns, it remains uncertain how much of the costs Army ultimately agreed to compensate. Soviet members of Allied Control Comission were not shy to demand all fruits of Finnish wartime weapons development with blueprints and full technical documents. Year 1946 they inspected 75 K/44 and a test-firing was organised for them. During this test the usual problems with firing mechanism and ejection of used cartridge case surfaced once again and as usual trail of gun carriage broke once more. Also the Soviets lost interest for this gun and allowed the Finns to keep the prototype.

Finnish Army was no longer interested about 75 K/44 with its focus now in new recoilless rifles, but Tampella decided to return to it one more time in year 1950. Several improvements were made to the design at that time, most important of which maybe being replacement of original spring recuperator of recoil mechanism with new pneumatic recuparator. Also firing mechanism and trails of gun carriage were improved. Tampella called the resulting improved prototype 75-mm antitank-gun model 1946. Around this time Tampella was doing close co-operation with Israeli Soltam, to which one of the prototypes was sent and never returned. Tampella manufactured also another prototype of this gun at that time and this prototype remained in Finland.

By end of World War 2 armour protection in heavy tanks had developed to such level that antitank-guns capable reliably penetrating their armour with armour-piercing ammunition needed to be so large and heavy that they could no longer be easily manhandled by their gun crew to firing position and off from it. The largest antitank-guns of the era, like German 12.8 cm Pak 44, were truly massive and impossible to be moved by hand. Hence the golden era of towed antitank-guns was already over, even if some countries still continued to develop and introduce new towed antitank-gun designs. On the long run heavy recoilless rifles and antitank-missiles started to replace them. When it comes to Finland the World War 2 era antitank-guns did a post-war career far exceeding their best-by date, the restrictions of Paris Peace Treaty from year 1947 were a major reason for this, since they forbid missiles from Finnish military and hence limited Finnish antitank-weapons inventory. While recoilless rifles proved suitable replacement for antitank-guns in most situations, their effective maximum range was notably shorter. Hence even captured Soviet 45-mm antitank-guns remained reserved for antitank-use until year 1960 and 75 PstK/40 remained reserved for such use until year 1986. One can't deny that not having a suitable domestic towed antitank-gun design could have been useful addition in whole era from 1950's to early 1980's.

 

300 Krh/42

(300 mm mortar model 1942)

PICTURE: 300 Krh/42 prototype manufactured by Tampella. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (160 KB).

Calibre:

300 mm

Barrel length:

512 cm

Weight in action:

? kg

Muzzle velocity:

? m/sec

Max. rate of fire:

up to ? shots / minute

Traverse:

? degrees

Elevation:

+ ? degrees, + 70 degrees

Min. range:

? meters

Max. range:

7500 meters (*)

Ammunition weight:

170 kg - 175 kg (HE)

Ammunition types:

HE

Country of origin:

Finland

Traverse: +/- 35 degrees (VTT mount) / 360 degrees (Tampella mount)

The idea for 300-mm super-heavy mortar originated from Hans Otto Donner (the driving force behind Tampella's weapons manufacturing), Aarne Tuomola (Chief of Tampella Weapons Department) and engineer Leo Jyväkorpi. They took the idea to General Vilho Petteri Nenonen (Inspector of Artillery at that time and often referred as "Father of Finnish field artillery"), who added his own views to the concept, which was a cheap super-heavy high-trajectory weapon designed for destroying bunkers and other fortications. It was Nenonen who appropriately nicknamed the weapon concept as "köyhän kansan Stuka" ("Poor nation's Stuka"), the nickname referring to well-known German Stuka-divebomber of that time.

Tampella started development work and completed the first blueprints in September of 1940. Finnish Ministry of Defense ordered 300-mm mortar barrel and base plate for the prototype from Tampella in June of 1941, but no bipod, ammunition or transport equipment. The mortar barrel of this caliber was somewhat outside the usual products of Finnish industry, so just few days later Tampella decided to order the barrel blank for it from Swedish Bofors, but due to technical difficulties in Bofors the delivery of barrel blank didn't happen until April of 1942. Tampella manufactured the mortar barrel and it was tested in Field Artillery Test Firing Centre in Niinisalo in summer of 1942. Since bipod didn't yet exist at the time the mortar base plate was dug in a hole and mortar barrel supported with wooden A-frame and wire attached to pulley. The mortar was test-fired the first time 1st of July 1942 with high-ranking officers (including Marshal Mannerheim, General Nenonen and Minister of Defence General Walden) observing the test-firing. The test was successful in that sense that the mortar successfully fired the sand-filled cast iron test projectiles.

Early 1943 Ordnance Department of Finnish Armed Forces General Headquarters had ordered Valtion Tykkitehdas (State Artillery Factory, VTT) to also design supporting structures for 300-mm mortar. The information caused considerable anxiety in Tampella, where this weapon was considered as their own invention, which was now in danger of slipping to their only domestic competitor. Tampella made official complaint about the matter and got Finnish military to transfer the order from State Artillery Factory to Tampella. March of 1943 Finnish military ordered six complete 300-mm mortars from Tampella. However also the previously ordered State Artillery Factories mortar design was completed and by using Tamplla's previously manufactured mortar barrel it was test-fired in spring of 1943.

While 300-mm mortar designed by Colonel A.E. Saloranta for for State Artillery Factory proved to work in these live-fire tests, the design had number of issues for which in the end Tampella had little reason to worry about competition. Following basic Stokes mortar design State Artillery Factory 300-mm mortar prototype had base plate and bipod attached to barrel with two buffers, but due to size and weight of both projectile and mortar it had few details which made the design somewhat challed as far as being field-worthy was concerned. Legs of the bipod were structurally telescopic and from their lower ends attached to small railway-like frame in which they could be moved. Moving the legs of the bipod off or towads each other allowed adjusting elevation upto 50 degrees and for larger elevations length of the bipod legs was adjusted. Hence adjusting the elevation was not easy and in case of the target not being with-in the weapons limited traverse, the whole would have to be disasembled and re-assembled in such manner that it would point toward the intended target. Hence the design was anything but practical for combat use. Due to shear size of the weapon and weigth of the mortar shell loading of the weapon was also quite complicated. State Artillery Factory 300-mm mortar prototype used special "elevator" permanently attached below barrel of the weapon for this purpose. Basically this elevator or loading arm was a large lever that was lowered to ground level for mortar shell and its propellant charge(s) to be installed into it. The elevator was raised and lowered with a wire host which had two wires going through a block attached to the muzzle. Once the elevator was loaded it was pulled back up until it reached muzzle of the barrel, at which point propellant charge and mortar shell were released and they slided into bottom of barrel. Needless to say the the loading system limited the weapons rate of fire and the idea of winching live high explosive shells already equipped with a fuse to height of 4 - 5 meters probably didn't exactly raise confidence to safety. Transport-wise this design had mortar barrel and bipod combination which was towed after a truck, while base plate and rail-section were. transported on truck equipped with lifting crane

PICTURE: 300 Krh/42 prototype manufactured by Tampella. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (184 KB).

Tampella come up with more practical structural design for the purpose. In their design mortar barrel was attached to monopod like lifting arm, which was attached to two axles which having tire and also to base plate. Unlike its competitor, Tampella's design allowed muzzle of the mortar barrel to be lowered to waist-level for reloading. Besides being more convenient, this also allowed higher rate of fire. Adjusting both elevation and traverse was easy and if the target was outside existing range of traverse, the whole mortar could be turned towards new direction relatively easy. Weigth of the weapon and hole in the ground required by the base plate being the obvious slow down factors for this.Tampella completed building the prototype in winter of 1943 - 1944 and it was test-fired in spring of 1944. The basic design proved to be a success, but still had a few handicaps, which needed to be ironed out before entering production. Test-firing memo dated 17th of May of 1944 lists these handicaps as:

Soon after this a misunderstanding caused development and manufacturing of the already ordered six weapon to be halted. But also the need for this sort of weapon was about to vaporate soon. It was only intended for destroying concrete fortifications while Finnish Army already had plenty of weapons more practical for other purposes. Once the Soviet offensive shifted the war from trench-war to mobile warfare in June of 1944, there were no longer need for weapon of this kind and when Continuation War ended in September of 1944 Finnish military cancelled all the previously made orders that it could. Due to final prototype still not being ready and delivery of the previously made order of six mortars being delayed, these orders were included to those about to be cancelled. End of October 1944 after negotiation held in Tampella Finnish Army officially cancelled them. Tampella considered this to be breach of contract and later in year 1946 demanded compensation of 5.1 million Finnish marks for the costs related to developing of 300-mm mortar.

One could claim that 300-mm mortar wasn't very practical weapon and possibly a sign of gigantism that effected German weapon designs like Maus possibly starting to seep also in Finnish planning. 300-mm mortar mortars would have required quite large resources when it to manpower and vehicles. Crew needed for a single mortar was 18 men and seven trucks were needed for transporting mortar, its equipment and ammunition. 203 H/17 super-heavy howitzers already existing in Finnish use could undoubtibly handle bunker-busting in most cases. However their projectiles were not in the same weight class as what those of 300-mm mortar, so in that sense 300-mm mortar could be expected to be notably more effective against concrete bunkers. While 203 H/17 APHE-shells weight 116-kg, mortar projectiles used in 300-mm mortar weight 170 - 175 kg and due to structural differences in between artillery and mortar shells much larger part of the mortar shell weight was high explosives.

Even if Finnish military didn't find any post-war use for 300 Krh/42, its manufacturer Tampella still found it some use. Later in 1950's Tampella used the technical design that it had developed for 300 Krh/42 in its new 160-mm mortar 160 Krh/57 160-mm mortar model 1957). While Finnish Army never acquired 160 Krh 57 in any real numbers, this mortar design was later manufactured by Soltam for Israeli military.

 

76 K/02-34 and 76 K/02-38

(76 mm field gun model 1902, modernized 1934)

(76 mm field gun model 1902, modernized 1938)

Before World War 2 Russian 76 K/02 (76 mm field gun model 1902) was de facto the standard light field gun of Finnish Army and also the most common field artillery piece in Finnish use. Being pre World War 1 design by 1930's it was already starting to become somewhat old-fashioned, so it is quite natural that at that time Finnish Army tried to develop suitable modernization for them. As with many field guns originating from pre-World War 1 era, the main problem of 76 K/02 field gun was maximum elevation limited by structure of its gun carriage, which resulted to notably smaller maximum range than what the gun was ballistics-wise capable.

Very little is known about 76 K/02-34, other than that at least one prototype was built and found to be unsuccessful. Presumably the changes made in 76 K/02-34 likely focused in developing the gun carriage, but neither the prototype or any drawings or photos seem to have survived to this day. Later 76 K/02-38 prototype is somewhat better known. It was built by Weapons Depot 1 (Asevarikko 1) in Helsinki by using normal 76 K/02 gun barrel and by modifying existing gun carriage. Basically the modification resulted actual gun barrel and breech with their recoil mechanisms being placed higher on gun carriage, which resulted maximum elevation increasing from about +17 degrees to about +35 degrees. Apparently two prototypes were built in 1938 - 1939 and were tested in autumn of 1939. Due to their higher center of gravity these prototypes proved notably less stable than original 76 K/02 and left (Inspector of Artillery) General Nenonen less than happy. Starting of Winter War ended Finnish Army development program for modernizing 76 K/02. During that war and Continuation War following it, Finnish Army captured large number of Soviet 76 K/02-30 field guns, in which the Soviets had solved the problem by equipping them with new kind of wider box trail that had a hole, which allowed higher maximum elevation for the gun. Finnish military decided to leave its existing 76 K/02 guns unmodified and used them as they were for the rest of their career.

 

76 RK/27-38

(76 mm regimental gun model 1927 - 1938)

PICTURE: 76 RK/27-38 infantry gun prototype. Photo taken in Weapons Depot 10 February of 1944. (SA-kuva photo archive, photo number 113503). CLICK THUMBNAIL TO SEE LARGER PIC (97 KB).

Apparently the idea for this infantry gun originated from Soviet 76 mm polkovaya pushka obr. 1943 g. which was basically earlier 76 mm regimental gun model 1927 installed to gun carriage of 45 mm antitank-gun model 1942. Needless to say the combination was notably lighter than original regimental gun version. The Soviet model 1943 gun developed by Tsiryulnikov was apparently successful, since it remained in production from year 1943 to end of World War 2 and provided the inspiration for Finnish prototype. Finnish Army experimented trying to create similar gun by installing captured 76-mm regimental gun on gun carriage of captured 45-mm antitank-gun model 1938 sometime around 1943 - 1944. Testing of the prototype revealed that the antitank-gun carriage could not handle the recoil, making the combination a failure. Since the special high-quality steel that was needed for making this modification was also in short supply, this project was abandoned.

While this was an interesting design, the main credit of the Soviet model 1943 gun seems to have been in simplifying of manufacturing - now that they used gun carriage of 45-mm antitank-gun they no longer needed to make separate gun carriage for 76-mm infantry guns. Compared to earlier regimental gun the resulting weapon was also somewhat lighter (weight in action 600 kg vs. 780 kg), which made the weapon somewhat easier for gun crew to manhandle. This would certainly have been useful when Finnish Army in summer of 1944 had to press captured 76 RK/27 and 76 RK/27-39 regimental guns to antitank-role (they had been equipped with HEAT-T ammunition suitable for that purpose). But considering the very limited Finnish industrial capacity the failure of this particular development project probably was not among the ones with most serious negative effects.

 

105 H/18-41

(105 mm howitzer model 1918 - 1941)

British World War 1 era 114 H/18 light howitzers were no longer among the best field artillery systems during Finnish - Soviet Continuation War (1941 - 1944). They were also only 114-mm artillery weapons in Finnish inventory, but Finnish Army still had 54 of them, which was relatively large number by Finnish standards of that day. So Finnish military decided to test developing prototype combining gun carriage of 114 H/18 with 105-mm howitzer barrel. According sources the barrel was either Czechoslovakian 105 H/41 barrel or Finnish 105 H/37 barrel manufactured by State Artillery Factory (Valtion Tykkitehdas) in year 1943. Ultimately this howitzer prototype proved to be too clumsy and the development project was abandoned.

 

105 H/18-44

(105 mm howitzer model 1918 - 1944)

PICTURE: 105 H/18-44 howitzer prototype. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (158 KB).

This was a second, later Finnish Continuation War era prototype designed for purpose of modernizing old-fashioned British 114 H/18 howitzer as 105-mm howitzer. This gun was tested year 1944. State Artillery Factory (Valtion Tykkitehdas) was again manufacturer of 105-mm howitzer barrel, which this time was 114-mm howitzer barrel relined for 105-mm ammunition, equipped with muzzle brake and new counter-weight system since the new barrel was somewhat more muzzle-heavy. Recoil mechanism of prototype howitzer proved to have problems handling the recoil forces and pressure levels created by notably more modern and powerful 105-mm howitzer ammunition. The prototype howitzer was estimated capable handling maximum muzzle velocity and pressure level of 400 meters/second and about 2,200 kg/square cm. Hence only reduced propellant charges used with existing 105 H/33 and 105 H/37 ammunition could be used, with maximum propellant charge being number 3 reduced propellant charge for 105 H/37 howitzer ammunition, which produced 390 m/sec muzzle velocity with 2,000 kg/square cm chamber pressure. As a result even with 105-mm howitzer ammunition the gun was not able to reach anywhere near the maximum range of modern 105-mm howitzers existing in Finnish inventory. The basic problem was that this howitzer tried to use original recoil system of 114 H/18, which was intended for ammunition that was considerably less powerful than what was usually used in later howitzers like 105 H/37, whose cartridge cases the prototype had been designed to use. Also breech mechanism received minor modifications. British dial sights for 114 H/18 had proved unsatisfactory, so this prototype was equipped with captured Soviet dial sight originally manufactured for 122 H/10-30 howitzer. Along many other projects also this one was abandoned due to ending of the Continuation War and resulting shutdown in armament development.

 

105 H/36-09

(105 mm howitzer model 1936-1909)

Finnish Army prototype for 105-mm light howitzer apparently built in 1930ís. This weapon combined gun carriage of old Russian/Soviet 122-mm H/09 howitzer with Bofors-manufactured 105-mm howitzer barrel. No further detail known at this time. The prototype has not survived and there are no known existing photographs.

 

105 KH/36 "Chilen tykki"

(105 mm gun howitzer model 1936, "The Gun of Chile")

PICTURE: 105 KH/36 with 105-mm howitzer barrel installed. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (114 KB).

Calibre:

105 mm x 764 R (field gun barrel)

150 mm / 152 mm (howitzer barrel)

Barrel length:

L/42 (with 105 mm barrel)

Weight in action:

3840 kg

Muzzle velocity:

700 - 775 m/sec (with 105 mm barrel)

Traverse:

+/- 30 degrees

Elevation:

- 5 degrees, + 45 degrees

Max. range:

15,1 km (with 105 mm barrel)

Ammunition weight:

15,1 kg (HE)

Ammunition types:

HE

Country of origin:

Sweden

This artillery piece prototype was equipped with two alternative barrels, 105-mm field gun barrel and 150/152-mm howitzer barrel, so with simple swap of barrel the same artillery piece could be used either as a heavy field gun or heavy howitzer. It was manufactured by Bofors in Sweden and what is known suggests that no written agreement had been signed concerning its order circa year 1935. Originally the gun was supposed to be delivered in year 1936, but for some reason the delivery was delayed until year 1940. The reason for acquiring this gun remains also unknown, it may have been bought to test suitability of the gun carriage for field gun and howitzer use or possibly for testing ammunition, but this just speculation.

While the howitzer barrel was also first ordered in 150-mm caliber, by May of 1940 this barrel had been changed into 152-mm caliber. It remains uncertain if the change of caliber happened already before manufacturing or if Bofors delivered it in 150-mm and it was later modified to 152-mm caliber in Finland. The reason behind caliber change is probably related to availability of ammunition, since Finnish Army already had number of old 152-mm Russian howitzers in use. The gun was commonly referred as "Chilen tykki" (The Gun of Chile), but the reason for this is no longer known. One theory suggests that cost of this gun may have been on similar level as possible financial donation from Chile during Winter War.

Unlike any other field artillery prototypes acquired by Finnish military, this gun was actually issued during the war and saw combat use. After its arrival to Finland in January of 1940 it was issued to coastal artillery, which used it with field gun barrel in Kaarnajoki coastal battery in eastern part of Karelian Isthmus for rest of Winter War. For Continuation War it was first issued to Fortification Artillery Battalion 4 (Linnoituspatteristo 4) and later to Saunasaari Coastal Fort in Lake Ladoga. The number of shots fired with this gun during Winter War is unknown, during Continuation War it was used to fire 731 shells with 105-mm barrel. Nowadays this artillery piece is in collections of Artillery Museum in Hämeenlinna.

 

150 Rkh/41

(150 mm rocket launcher model 1941)

PICTURE: 150 Rkh 41 rocket launcher. This is the only surviver of the 15 launchers that Finland bought from Germany during World War 2. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (86 KB).

Calibre:

158.5 mm

Lenght of barrels:

130 cm, L/8.2

Weight in action:

770 kg (loaded)

Muzzle velocity:

340 m/sec

Traverse:

+/- 24 or 27 degrees

Elevation:

- 5 degrees, + 45 degrees

Max. range:

6.9 km

Ammunition weight:

35.9 kg (HE)

Ammunition types:

HE and smoke (*)

Country of origin:

Germany

(*) German military used also smoke and propaganda rockets and had chemical rockets in storage But only high explosive (HE) rockets were delivered to Finland.

This was German 15 cm nebelwerfer 41 multiple rocket launcher. Early German 10-cm nebelwerfers ("fog throwers") were mortars designed for shooting smoke and other chemical projectiles and later on also high explosive shells, but later the name nebelwerfer was used also about multiple rocket launchers introduced for the same purposes. 15 cm nebelwerfer 41 was introduced to use of German military in year 1940. The Germans had started development of artillery rockets already in 1920ís, but this was one of the first successful designs that they fielded. It used spin-stabilized rockets equipped with high explosive, smoke, or chemical warheads. The launcher had six barrels and was placed on gun carriage of 3.7 cm Pak 35/36 (37 PstK/37) antitank-gun, which had been equipped with one additional folding support arm. Propellant used in the rockets was normal gunpowder, which was ignited electrically. Rockets used this launcher were technically quite complicated with the rocket designs used in later German multiple rocket launchers being notably less difficult to manufacture. Once loaded the launcher could fire one rocket every two seconds or so, all six rockets could be fired in 10 - 12 seconds and three salvos of six rockets in about five minutes. Launching of rockets happened with remote control and required crew to take cover due to pressure waves and flames created by the burning propellant. German industry manufactured about 6,000 of 15 cm nebelwerfer 41 and some 5.5 million rockets for them.

Finnish Army bought 15 of these multiple rocket launchers from Germany in year 1944. They were delivered in two delivery batches, from which the first delivery batch of 7 launchers arrived with S/S Capella 21st of February 1944 but the second delivery batch of 8 launchers didnít arrive until August of 1944. These 15 launchers, spare parts, tools and ammunition were issued new unit created especially for them. That new unit was Light Smoke-thrower Battalion 1 (Kevyt Savunheitinpatteristo 1), which was trained in Niinisalo. Apparently the Germans delivered only some 2,200 high-explosive (HE) rockets for these weapons. While this unit was created and trained, it didnít see combat service because of three reasons. The most serious of these reasons was probably the delay of 2nd delivery batch, due to which the unit wasnít properly equipped weapons-wise until too late date to complete its training.

The second reason was rather limited number of rockets, while 2,200 rockets was plenty for training, it wasnít very little for combat use (*). The third reason was tactics-related. Due to massive launch signature units using this sort of multiple rocket launchers would be obvious to spot for enemy artillery forward observation teams, so counter battery artillery was a major problem. The Germans had a simple solution for the problem Ė they typically used "shoot and scoot" tactics, with nebelwerfer units frequently changing fire positions before enemy artillery would be able to respond. Germany never delivered the fast towing tractors needed for this, which left the unit without proper towing vehicles for its rocket launchers. Unit of this type required large number of motor vehicles and fuel (**), which by 1944 were starting to be limited in very limited supply. While some sources claim otherwise according original ship cargo manifests also smoke rockets were delivered to Finland in 1944 (***).

(*) Typical ammo load for German nebelwerfer battalion equipped with 18 x 15-cm nebelwerfer was 2,160 rockets, in other words 1,728 high explosive rockets and 432 smoke rockets.

(**) German nebelwerfer battalion organization with 18 x 15 cm nebelwerfer had no less than 109 motor vehicles and 9 motorcycles.

(***) S/S Baltic arrived to Finland 8th of March 1944 with cargo containing 784 smoke rockets and 816 high-explosive rockets for these multiple rocket launchers. In other words total 1,600 rockets.

After World War 2 these launchers were used for live fire training and display the effects of artillery rockets, but they saw relatively little post-war use. Nowadays only surviving sample of the 15 launchers delivered to Finland is in collections of Artillery Museum in Hämeenlinna.

 

280 Rkh/43

(280 mm rocket launcher model 1943)

PICTURE: 280 Rkh 43 rocket launcher prototype. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (105 KB).

Calibre:

282 mm

Length of barrels:

130 cm, L/4.6

Weight in action:

? kg

Muzzle velocity:

? m/sec

Traverse:

+/- ? degrees

Elevation:

- ? degrees, + ? degrees

Max. range:

1.2 - 2.5 km / 2.2 km (last design)

Ammunition weight:

60 - 86 kg (HE)

Ammunition types:

HE

Country of origin:

Finland

Year 1943 Finnish Army tried to buy heavy multiple rocket launchers from Germany, but the Germans refused to sell any. Finnish military decided to solve the problem by developing heavy multiple artillery rocket launcher of its own. The resulting Finnish 280-mm rocket launcher design was based to German nebelwerfer designs, but the rocket design loaned heavily from design of dud Soviet katyusha rocket, which Finnish troops had recovered. Early on there were problems related developing of gunpowder suitable to be used as rocket propellant, but this problem was solved. The rockets and launcher prototypes were tested in Niinisalo from February to October of 1944. Early launcher designs were simple launching frame, but already before the project entered to test-firing stage, these had been replaced with two-barrel launcher designed and build by State Artillery Factory (Valtion Tykkitehdas, VTT). Later this two-barrel launcher was replaced second prototype, which was four-barrel launcher design build in light antitank-gun carriage like platform. Finnish-developed rockets were all high-explosive (HE) variety and their weight varied around 60 Ė 86 kg. During final tests in October of 1944 this rocket launcher was compared against captured German 280-mm multiple rocket launcher captured in Lapland War and proved to be about equally effective, if not slightly better. Decision about putting this weapon into mass-production was already made in October of 1944, but cancelled before the production started along other new projects cancelled at that time. Nowadays the 2nd prototype is in collections of Artillery Museum in Hämeenlinna.

Finnish military had started its development work with artillery rockets already some time before 280-mm rocket launcher project. Originally this work started in year 1942. Early development had taken considerable time with very little actual progress, since only real Finnish gunpowder manufacturer State Gunpowder Factory (Valtion Ruutitehda, VRT) had not been able to provide gunpowder, which would have suited as a propellant for this purpose. These experiments had started with use of captured Soviet artillery rockets being used as control group against which Finnish-developed rocket were tested. Rocket launcher used for the test purposes was a captured Soviet launcher which had been on temporary bases attached to bipod originating from 50-mm mortar. Since this seems to have been single launcher, it is possible that the captured test-launcher may have originated from downed Soviet aircraft. VRT started providing gunpowder suitable for this use in late December 1942 and first test-firing of artillery rockets was performed 29th of January 1943. This first Finnish-manufactured artillery rocket was 82-mm caliber and presumably either copy or at least heavily based to Soviet RS-82 artillery rocket, against which it apparently was tested.

PICTURE: 280 Rkh 43 rocket launcher prototype. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (169 KB).

In this first test-firing the launcher was propped to fire the rockets at 45 degree angle and performance of each fired rocket was measured. During the test six captured Soviet rockets and four Finnish-manufactured rockets were fired. Test results revealed that the Finnish-manufactured rockets achieved basically similar range (5,078 meters vs. 5070 meters) as the Soviet ones and laterally showed almost equally poor accuracy (460 meters vs. 610 meters) as the Soviet ones. However what made test successful was the remarkably better lengthwise accuracy of Finnish-made rockets - lengthwise their dispersion pattern in target area being only 30 meters vs. 265 meters of Soviet-made rockets. It is worth noting that the launcher setup used for testing was rather unstable and according test report this may be caused at least partially the very poor lateral accuracy of the tested rockets.

While these early 82-mm Finnish experimental artillery rockets had been manufactured in Weapons Depot 1 (Asevarikko 1, AV 1), it lacked the manufacturing capacity for making them anytime soon even in the limited numbers required just for testing purposes. Hence due to this reason the order of 50 test rockets made following the first test-firing was transferred from AV 1 to State Artillery Factory (Valtion Tykkitehdas, VTT). Also prototype multiple rocket launcher for six rockets was developed at that time and new 122-mm artillery rocket was under planning with its blueprints being expected to be completed by April of 1943. This Finnish 122-mm artillery rocket prototype was based to dud Soviet 132-mm artillery rocket (presumably RS-132), but its warhead was 122 tkr v 32/41 high explosive artillery shell. It remains unclear if the 122-mm rocket reached prototype stage. However what can be noted with certainty is that none of the Finnish artillery rockets reached mass-production or combat-use.

 


SOURCES:

Field Rocket Equipment of the German Army 1939 - 1945 by T.J. Gander.

Panzerfaust and other infantry anti-tank weapons by Wolfgang Fleischer

Tampellasta Patriaan by Vesa Toivonen.

Itsenäisen Suomen kenttätykit 1918 Ė 1995 by Jyri Paulaharju.

Tykistömuseon 78 tykkiä by Unto Partanen.

Ilmatorjuntamuseo-opas by Raimo Vehviläinen

Military Small Arms in Finland part 2 by Markku Palokangas.

Aimo Lahti, asesuunnittelun suuri suomalainen by Markku Palokangas and Maire Vaajakallio.

Suomi-konepistoolin tarina by Timo Hyytinen and Harri Hyytinen.

Finnish National Archives, archive folder T19051/32

Finnish National Archives, archive folder T19049/7.

Finnish National Archives, archive folder T19051/32.

Finnish National Archives, archive folder T19052.

Field Rocket Equipment of the German Army 1939 - 1945 by T.J. Gander.

Stalin Organs, Russian Rocket Launchers by Michael Foedrowitz.

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

Special thanks to Ilmatorjuntamuseo (Finnish Antiaircraft Museum), Tuusula.

Special thanks to Tykistömuseo (Finnish Artillery Museum), Hämeenlinna.


Last updated 8th of September 2013
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