MINE THROWERS & MORTARS

PART 6

120 mm mortars:

 

120 Krh/38

(120mm mortar model 1938)

(120-HM 38)

PICTURE: Soviet 120 Krh/38 mortar. (Photo taken in Museum of Artillery, Sappers and Signal Corps in St. Petersburg, Russia). CLICK THUMBNAIL TO SEE LARGER PIC (151 KB).

Calibre:

120 mm

Barrel length:

186.2 cm

Weight in action:

256 kg or 275 kg

Muzzle velocity:

119 - 272 m/sec

Max. rate of fire:

up to 20 shots / minute

Traverse:

6 degrees

Elevation:

+ 45 degrees, + 80 degrees

Min. range:

1380 meters

Max. range:

6000 meters (*)

Ammunition weight:

15.6 kg - 16.0 kg (HE) + 23.9 kg (HE)

Ammunition types:

HE

Country of origin:

Soviet Union

(*) With mortar shells weighting 15.6 - 16.0 kg. With heavy mortar shells weighting 23.9 kg the maximum range was only about 4,000 meters.

Finnish use: About 200 Soviet 120 were captured during Continuation War (1941 - 1944). In addition to this Finland bought 50 of these mortars from Germany in year 1943. Large numbers of these mortars were re-issued to Finnish troops during Continuation War.

This weapon, 120-mm Soviet regimental mortar model 1938, was basically a scaled up version of 82-mm battalion mortar model 1937. Structurally the mortar was conventional Stokes-Brandt related design divided to base plate (weight some 94 kg), bipod (about 62 kg) and barrel (about 100 kg). It was transported on similar one-axle two-wheeled limber as 107 mm regimental mortar model 1938, but its the towing system included usually also one-axle two-wheeled ammunition cart, which contained 20 mortar shells. The Soviets had both normal and heavy high explosive shells for this mortar. The normal 16-kg mortar shell contained about 2.7-kg of explosive, while the heavy mortar shell weight 23.9-kg and contained 7.6-kg of explosive. What is known during Winter War the Soviets still didn't yet have their 120-mm mortars in large-scale production. At the time they also seem to have still been secret weapon, which the Soviets were only field-testing in battles of Winter War. It also seems that the Finns didn't notice existence of these new heavy Soviet mortars either. So when Germany attacked Soviet Union in summer of 1941 the Germans were still unaware about their existence. 120-HM 38 mortar soon proved to be highly successful design, indeed many might argue that it was one of the very best mortar designs of World War 2. The mortar shells it fired were powerful enough to do serious damage, it had a good maximum range, remarkable mobility and taking it in or out of action was both easy and quite fast to move from one place to another. In fact the captured mortars of this model impressed the Germans so much, that not only took the captured 120-HM 38 to their own use as 12 cm GrW 378(r). But they also reverse engineered it and starting manufacturing their own copies, which they named 12 cm GrW 42. During World War 2 the Soviets developed also new version of this mortar called 120-HM 43, which was otherwise similar to 120-HM 38, but it had only single shock absorber on the barrel-bipod mounting. By end of World War 2 estimated Soviet production of 120-mm mortars totalled over 12,000 mortars.

Barrel and breech of 120 Krh/38 weight about 100-kg. Base plate weight about 94-kg and bipod about 62-kg. The weapon had removable transport carriage and limber. During transport the mortar with its transport carriage weight about 490-kg. When also limber was included the weapon + transport carriage + limber with ammunition they reached total weight of 1,150-kg. The firing mechanism of this mortar had settings - one which fired it automatically when mortar shell was dropped to barrel and another setting which allowed firing each shot with trigger (attached to lanyard). Limber of this mortar could contain 20 mortar shells with propellant charges and fuses needed for them.

Finnish Army captured its first Soviet 120-cm mortars in year 1941 and named them 120 Krh/38 (120 mm mortar model 1938). The total number of these mortars captured during Continuation War was around 200. Practically all of them were HM 38, but there were also at least 17 mortars 120-HM 43 (120 Krh/38-42 for the Finnish Army) among the Soviet mortars captured in year 1944. Year 1943 Finland also bought from Germany 50 of these mortars. They arrived with S/S Norma 4th of April 1943. Since these 50 mortars were lacking limbers and mortar directors they could not be issued right away. During Continuation War Finnish industry was manufacturing improved limber (which allowed faster motorised towing) for these captured mortars. During Continuation War Finnish Army re-issued captured 120-mm in large numbers to combat troops, for example 1st of June 1944 Finnish Army inventory contained 187 of these mortars and 122 of them were issued to frontline troops. Since in addition to captured ammunition also Finnish 120-mm mortar ammunition could be used in these mortars there was no real danger of ammunition shortage. During Continuation War these mortars saw plenty of combat use with Finnish troops. They proved effective and well liked, but since the Finns had also their mortar design (120 Krh/40), year 1944 Ordnance Department of Finnish Armed Forces General Headquarters asked feedback concerning these two mortars from the troops.

When combined the feedback letters offer the following view:

"The base plate of 120 Krh/38 is bigger and has a better form - it stays well in its place and sinks less to the ground than base plate of 120 Krh/40. Firing mechanism not included the weapon is solid and accurate. However this mortar is clumsier and heavier to transport than 120 Krh/40. The firing mechanism is unnecessarily complicated and malfunctions much too easily. The bottom of barrel is too weak. Screws of the bipod are unprotected and the thread of elevation setting system too steep. The recoil system is simple, but after recoil it does not return always to exactly the same position. Conclusion: 120 Krh/40 is superior in all other areas, but 120 Krh/38 has a better base plate."

PICTURE: Captured 120 Krh/38 mortar modified in Finland to be horse-towed. This Finnish towing system used with 120-mm mortars was simple yet effective since it used only horse towing the mortar. Photo taken in November of 1942. (SA-kuva photo archive, photo number 113145). CLICK THUMBNAIL TO SEE LARGER PIC (103 KB).

Since they were in large-scale frontline use Finnish Army lost quite a few 120 Krh/38 mortars in battles of summer 1944. Thirteen of these mortars were lost in just about a month of the most intensive fighting. After World War 2 captured Soviet 120-mm mortars remained in use of Finnish Army, but since 120 Krh/40 was also available in large numbers the captured mortars saw much less action in training use. Still large numbers of them have remained warehoused to this day.

Losses of 120 Krh/38 mortars 9th of June - 7th of July 1944:

Unit:

Losses:

II Army Corps

0

III Army Corps

0

IV Army Corps

6

V Army Corps

6

Aunus Group

1

14th Division

0

Finnish Navy

0

Ladoga Coastal Brigade

0

Total:

13

Around 1941 Ė 1942 Finnish Army experimented using 120 Krh/38 as field artillery weapon (like the Soviets used them). For this experimentation Finnish Army had formed field artillery unit named Kranaatinheitinpatteristo 1 (Mortar Artillery Battalion 1). The experiment seemingly proved quite successful, but the unit was disbanded in early spring of 1942. The official reason for disbanding it was ammunition shortage, but the real reason behind it seems to have been bureaucratic decision for keeping mortars with infantry weapons instead of issuing them also to field artillery.

Captured ammunition Finnish Army used with Soviet 120-mm mortars during WW2:

name of mortar shell:

Weight (*):

shell length:

fuse:

# of additional charges:

# of wings:

filled with:

country of origin:

120 tkr-12-V 36/40-GBM3

15.57 kg

64.0 cm

Soviet 36/40 GBM3

6 x 120 Krh/38 lpv

12

TNT

Soviet Union

120 akr-12-V 36/40-GBM3

15.57 kg

64.0 cm

Soviet 36/40 GBM3

6 x 120 Krh/38 lpv

12

amatol

Soviet Union

120 vrtkr-12-V 36/40-GBM3

15.57 kg

64.0 cm

Soviet 36/40 GBM3

4 x 120 Krh/38 lpv

12

TNT

Soviet Union

120 vrakr-12-V 36/40-GBM3

15.57 kg

64.0 cm

Soviet 36/40 GBM3

4 x 120 Krh/38 lpv

12

amatol

Soviet Union

120 p tkr-12-V 36/40-GBM3

16.00 kg

70.0 cm

Soviet 36/40 GBM3

4 x 120 Krh/38 lpv

12

TNT

Soviet Union

120 p tkr-2 x 12-V 36/40-GBM3

23.9 kg

106.1 cm

Soviet 36/40 GBM3

?

2 x 12

TNT

Soviet Union

Notice: 120 tkr-12-V 36/40-GBM3 and 120 akr-12-V 36/40-GBM3 were OF-843 in Soviet naming system. 120 vrtkr-12-V 36/40-GBM3 and 120 vrakr-12-V 36/40-GBM3 were OF-843A in Soviet naming system. 120 p tkr-12-V 36/40-GBM3 was F-843 in Soviet naming system.

Notice: Also Finnish mortar shells manufactured for 120 Krh/40 mortar could be used with captured Soviet 120-mm mortars, but breech of these Soviet mortars proved too weak for long term use of Finnish mortar shells. So the Finns first reinforced the breech in many captured 120-mm mortars and later replaced their breech with the one used in 120 Krh/40.

 

120 Krh/40

(120 mm mortar model 1940)

(120 mm granatkastare m/41)

PICTURE: 120 Krh/40 mortar. Mortar director seems to be post-WW2 model. (Photo taken in Tykistömuseo). CLICK THUMBNAIL TO SEE LARGER PIC (100 KB).

Calibre:

120 mm

Barrel length:

189 cm

Weight in action:

260 kg

Muzzle velocity:

116 - 290 m/sec

Max. rate of fire:

up to 20 shots / minute

Traverse:

? degrees

Elevation:

+ ? degrees, + ? degrees

Min. range:

600 meters

Max. range:

5300 meters

Ammunition weight:

12.5 kg (HE)

Ammunition types:

HE

Country of origin:

Finland

Finnish use: Manufacturing of this mortar started after Winter War. By starting of Continuation War Finnish Army had 162 of them. By end of year 1943 almost a hundred more were delivered. During Continuation War these mortars were the standard heavy mortars of Finnish Army.

This was Finnish mortar design developed by Tampella. In early 1930's Tampella started developing also 120-mm mortar, as 81-mm mortars were not very effective against dug-in troops. Developing of 120-mm mortar proved to be quite easy, but on the other hand developing 120-mm mortar shell with effective ballistics proved much more difficult. By mid-1930ís Tampella had managed to solve the ammunition development problem and had both 120-mm mortar and its ammunition ready for production. But, at that point selling the new heavy mortar proved problematic. "Saving" was word of the day in defence funding in Finland so funding reserved for heavy mortars was cut off from defence purchases of 1935. Heavy mortar didnít return back to Finnish Army shopping list until year 1939 and at that time getting the purchase accepted was already too late - Winter War started in November of 1939 and Finnish troops had no heavy mortars. When Finnish military finally ordered 120 heavy mortars from Tampella in December of 1939 the war had already begun. As production capacity and raw materials during this war were needed elsewhere the first heavy mortars were not issued until late 1940.

However the delay in introducing 120-mm Tampella mortar to production had also some positive effects. The mortar prototype may have been already completed as a finished product in year 1936, but since its development continued the whole time from 1935 to 1939 the resulting weapon and its ammunition were much more refined and effective than what the prototype of year 1936 offered. For example during this long development the maximum shooting range was increased considerably. At the same time the development succeeded also improving shooting accuracy of the weapon. The final development version, which went to mass production Tampella called 120 Krh/35/39 (120 mm mortar model 1935/1939) and Finnish Armed Forces named it 120 Krh/40 (120 mm mortar model 1940)

Main improvements introduced during this development:

    1. Firing system, which was drop-fire type (when mortar bomb was dropped to mortar barrel it was fired immediately once it hit bottom of the barrel).
    2. Improved base plate design.
    3. Mortar barrel was lightened (reducing weight of the weapon).
    4. Development of transport- and ammunition limber was completed (it was ordered year 1937).
    5. Further development of mortar shells and propellant charges.

After Winter War the production of Tampella 120-mm mortar was finally started. Finnish Army received its first 120 Krh/40 mortars late 1940. Once the 160 mortars of the first order were delivered Tampella continued the production manufacturing 45 additional mortars for Finnish Army in year 1941. What happened after this is considered controversial move at best - deliveries of 120 Krh/40 to Finnish Armed Forces were stopped and instead exporting them to Sweden begun. Year 1942 Finnish military received no 120-mm mortars from Tampella and production of the whole year went to Sweden. In years 1943 - 1944 about half of the production was still exported to Sweden. Considering Finland was in middle of fighting a war, while Sweden wasn't, finding understanding for the reasons why Finland decided to sell large part its newest and best weaponry to Sweden at that time instead of using them to reinforce its own troops can be difficult. The basic reason behind this export was the cruel necessity of economy. Finnish industry depended largely to raw-materials provided by Sweden and to pay these the Finns had to provide some products, which the Swedes were interested to buy - and Tampella 120-mm mortar was exactly such a product. The other piece in the puzzle was that Finnish Army apparently didnít at the time consider expanding the number of 120 Krh/40 in its disposal to be that important. Tampella asked Ordnance Department of Finnish Armed Forces GHQ permission for exporting the mortars in beforehand - and received it.

Deliveries of 120 Krh/40 mortars to Finnish Army:

Year:

Delivered:

1940

94

1941

102

1942

0

1943

60

1944

31

1945

70

1946

20

Total:

377

Notice: There seems to be small discrepancy in numbers. Some sources claim that the number of 120 Krh/40 delivered to Finnish Army was 371.

Exports of 120 Krh/40 mortars to Sweden:

Year:

Delivered:

1941 - 1942

120

1943

50

1944

49

Total:

219

Notice: Again there seems to be small discrepancy in numbers. Some sources claim that 215 of these mortars were exported to Sweden.

In either way during 1941 - 1943 Finnish Armed Forces received 256 of these mortars. When Continuation War begun in June of 1941 Finnish military had already 162 of them. At least part of mortars delivered in year 1944 may have been delivered only after Continuation War had already ended. By end of year 1945 Finnish military had received 357 (or according some sources 351) of them. In addition Swedish military received 219 (or according some sources 215) of these same mortars and Sweden acquired also license for manufacturing them. Swedish military knew them as 120 mm granatkastare m/41 (120mm GrK m/41). Swedish license manufacturers of this mortar included Motala, HVA and Electrolux. In addition to 120-mm mortars also large amounts of ammunition for them was exported to Sweden during World War 2.

PICTURE: Another 120 Krh/40 mortar. (Photo taken in Sotamuseo). CLICK THUMBNAIL TO SEE LARGER PIC (93 KB).

During Continuation War 120 Krh/40 proved excellent weapon. It had good range, effective ammunition and excellent mobility. The mortar was transported on one axle limber, which had two wheels. Basic structure of the mortar was the typical Stokes Brandt based, which was divided to three main parts: Mortar barrel (weight 85 kg), bipod (weight 68 kg) and base plate (weight 100 kg). The weapon's weight was about 390 kg with equipment in transport and was suitable both for motorised towing and to be towed with a horse. Wartime mortar shells weight about 12.49-kg and contained about 2.2-kg of TNT. Year 1944 Ordnance Department of Finnish Armed Forces GHQ requested feedback concerning 120 Krh/38 and 120 Krh/40 mortars.

When combined the feedback letters offer the following view:

"120 Krh/40 is easier and faster to handle and easier to transport in difficult terrain. The recoil system is better (the mortar returns exactly the same position each time after recoil - which allows faster rate of fire and less need for correcting aim during shooting. Elevation and stabilisation adjustments are good. Weakness: The compartments in bottom of the base plate get filled easily, when this happens they form a return surface on which the mortar starts gliding sideways during shooting. The stabilisation adjustments are the same side as aiming adjustments - making aiming faster. When laid the mortar has less play than with 120 Krh/38. The screws of mechanisms are protected and the thread more durable. The recoil mechanism is more rigid, which allows it to maintain elevation setting more accurately during shooting and firing mechanism is more reliable. Conclusion: 120 Krh/40 superior when compared to 120 Krh/38 all other areas except 120 Krh/38 has better form of base plate."

During Continuation War Finnish Army issued 120-mm mortars first to regimental mortar platoons (of infantry regiments), most if not all had early on mix of 81-mm and 120-mm mortars. Already around 1942 these regimental mortar platoons were replaced with regimental mortar companies, which were armed with 120-mm mortars only and while this company early on had just two platoons by end of the war most had three platoons, which each had 3 mortars. Due to large number of 120 Krh/40 mortars in combat use also their losses during heavy fighting of summer 1944 were quite notable, but Finnish Army was able to replace them swiftly. During the most active month or so no less than 34 were lost. When Continuation War ended Finnish military had just started placed new order of 180 mortars 120 Krh/40, even if Finnish military decided to reduce the order to 50 mortars Tampella decided to continue their production, which caused considerable argument between the two parties.

Losses of 120 Krh/40 mortars 9th of June - 7th of July 1944:

Unit:

Losses:

II Army Corps

0

III Army Corps

9

IV Army Corps

3

V Army Corps

14

Aunus Group

4

14th Division

0

Finnish Navy

4

Ladoga Coastal Brigade

0

Total:

34

Career of 120 Krh/40 mortars in use of Finnish Army continued well to 1990's and some may still remain warehoused for possible wartime use. Post-WW2 towed heavy mortars that Tampella / Vammas (1991 - 1997) / Patria (1997 - to this day) manufactured for Finnish Defence Forces contain:

Ammunition Finnish Army used with 120 Krh/40 during WW2:

name of mortar shell:

weight (*):

shell length:

fuse:

# of additional charges:

# of wings:

filled with:

country of origin:

120 tkr-10-32/41-35

12.49 kg

51.5 cm

Finnish 32/41

3 x 120 Krh lp 90 /

10

TNT

Finland

2 x 120 Krh lp 30 /

7 x 120 Krh lp

120 tkr-10-24/31-Ra

12.49 kg

51.5 cm

French 24/31

same

10

TNT

France?

When it came to 120-mm mortar ammunition Finland was self-sufficient - domestic industry was capable manufacturing enough and buying more from foreign sources was not necessary. Only possible exception to this rule seems to have been one mortar shell model (120 tkr-10-24/31-Ra) using French fuse, but these may have also been Finnish-made. VTT (Valtion Tykkitehdas = State Artillery Factory) and Ammus Oy manufactured blanks for 120-mm mortar shells. Tampella, Ammus Oy and Wårdström machined completed mortar shells from these blanks. Tampella was the biggest manufacturer as it manufactured about half of the 120-mm mortar shells. The total Finnish production of 120-mm mortar shells during World War 2 was bit over million shells, from which about 300,000 still remained in warehouses after the war. One source suggests that during late Continuation War project for developing heavier mortar shell for 120 Krh/40 may have existed. If such a project did indeed exist, it does not seem to have resulted in any real production.

 


Source materials used for making these mortar pages listed on bottom of MINETHROWERS AND MORTARS PART 7.

.
Last updated 12th of July 2015
Webmaster: JTV jtvalias@hotmail.com
Copyrights (pictures, text and graphics): Jaeger Platoon Website.