26 June 2013

Falschirmjaeger just about ready for action in 20 mm FOW

I have been slowly building up my 20mm WW2 armies over the last year, switching from Warhammer WW2 rules to Flames of War. This meant re-basing my entire collection.

The Normandy Brits are done, as are my original Falschirmjaeger, and now I am working on expanding my force. Planning on a game against Luc at the Kapiti Wargames Club Open Day on Sunday.

Early war (R) and late war uniforms. In Crete a Sand-coloured uniform was worn.

As mentioned before I decided to go with an autumn theme rather than the more usual summer or winter. This makes the range of figures that are useful larger, being able to field both winter and summer uniforms (I.e. guys that are cold, and ones that are not so cold, and still wearing the summer uniforms, albeit with the autumn camouflage outside)

My elite troops are painted in the Autumn Oak or planatin Camo, and my Falschirmjaeger in the yellower variant of the Splintermunster camo smocks, with the blue luftwaffe trousers and blue or luftwaffe camo green helmets.

Images from across the net. Reproduction uniform images from Spearhead Militaria
This is also a good site for info on uniforms in general.

FJ pictures part 6-zpaxvy4dg2cd.jpg

This enlarges the scope of games that can be played authentically dramatically, with both winter and summer terrain becoming useful. I used red "iron ore: ballast from the railway miniatures range as the base, and added  lichen in various colours. The result is quite pleasing to they eye, but also vividly illustrates how effective the German Late-war autumn camo was.

"Blurred Edge Autumn Scheme"

"Autumn Oak A Camo"

"Oak B" Camo

Autumn Plantain Leaf no 4

Autumn Plantain Leaf no 2

Plantain leaf no 5 Autumn side

Pea Dot 44 Camo

17 June 2013

Horsing around: Revell's German Horse-drawn artillery leFH 18 and Cossacks

Horsing Around: German WW2 Horse-drawn 105mm Light Field Artillery

Modelling Revell's leFH 18 Horsedrawn kit and Cossacks

I seem to have developed a Russian/East front theme to my modelling and painting in the last week. First the IS-2s and now the Revell Cossacks, throwing in the Cossack with a horse on foot strangely included in their Infantry set. 

Have been basing the infantry for FoW, then worked on the Cossack Cavalry. Whilst most modelers will bemoan the presence of the Cossack on foot in the infantry set, I found it useful. The Cossacks can dismount in FoW, send their horses to the rear, and fight on as regular infantry. The dismounted guy will be useful for this, and can also double as an officer with the seated officer with binoculars from the Cossack set for  unit command .

Photographs nicked from Plastic Soldier Review. 
An excellent site about our passion. Recommended reference.

Having built and based these guys I thought I'd stick with the horse theme, and proceeded to work on the German Field Artillery with the LeFH 18 10.5cm field guns. Much to my delight the guns are very detailed, more so than the Zvezda kits I have used before. 

In fact on the table it can be hard to distinguish the Zvezda LeFH 18 from a PAK 40. With the Revell kits there are no doubts.The reason is that two different carraiges are modeled, the earlier model with spoked wheel, the latter with the Pak 40s carriage. The Revell kit also does not have the muzzle brake.

See details below.

German leFH18: 

The 10.5 cm leFH 18 (German: leichte FeldHaubitze "light field howitzer") was a German light howitzer used in World War II.

The 10.5 cm leFH 18 was the standard divisional field howitzer used by the Wehrmacht during the Second World War. It was designed and developed by Rheinmetall in 1929-30 and entered service with the Wehrmacht in 1935. Generally it did not equip independent artillery battalions until after the Battle of Stalingrad in 1943. Before 1938 the leFH 18 was exported to Hungary and Spain. 53 were also exported to Finland.

It had a heavy, simple breech mechanism with a hydro-pneumatic recoil system. The 10.5 cm leFH 18 had wood-spoked or pressed steel wheels. The former were only suitable for horse traction. Initially, it was not fitted with a muzzle brake. In 1941 a muzzle brake was fitted to allow longer range charges to be fired. This increased the range by about 1,800 yards and was known as the leFH 18M. 

In March 1942 a requirement was issued for a lighter howitzer. This led to a second modification, known as the leFH 18/40. This modification consisted of mounting the barrel of an leFH 18M on the carriage for a 7.5 cm PaK 40 antitank gun. The new carriage increased the rate of fire as well as making the howitzer lighter. Additionally, a more efficient muzzle brake was added, decreasing the recoil. Ballistically, the 10.5 cm leFH 18M and the leFH 18/40 are identical.

During the French campaign the leFH 18 was often pressed into service in the anti-tank role when isolated pockets of heavily armoured French tanks, like the Char B and Somua, made breakthroughs. The 10.cm leFH 18 and the famed "88" were often the only weapons available.

While its weight proved useful in its sturdy construction and as a stable firing platform, it was a draw back when it came to manoeuvrability. It weighed 1985 kgs, which increased to 2050 kgs once the muzzle brake was added. During the Russian winter of 1941/42 the mud proved too much for many leFH 18. Many were abandoned to be captured by the Soviets when their crews could not drag them from the mud. Despite being designed with motor traction in mind, the German artillery still relied heavily on horse drawn limbers as it’s main means of motive power.

During 1942 thought was put into how to over come this design flaw. The final result was the leFH 18/40 which utilised the much lighter PaK 40 trail and wheels (wider wheels were introduced later) for its carriage, though the result wasn’t substantially lighter than its predecessor, 1900 kgs, its was put into production in 1942. The leFH 18 continued to be the main form of artillery in the German army, the introduction of the leFH 18/40 merely supplementing those already in service.

A total of 6986 leFH 18s and 10265 leFH 18/40s were manufactured during the war to add to those already in service in 1939.

The Germans did consider a complete redesign, Krupp, Rheinmetall and Skoda put new designs forward, but none of these designs were adopted.The 10.5 cm leFH 18 howitzer was a good weapon that served the Wehrmacht well. It maybe thought of as the plain Jane of the German gun arsenal when compared to more glamorous contenders like the 8.8cm FlaK 36 and the 7.5 cm PaK 40, but in overall damage done to the Allies the leFH 18 would be hard to beat.  

14 June 2013

Russian stash growing: Unexpected Divisional reinforcements for the CCCP

Divisional Support for Strelkovy and Tankovy (...and more Germans)

I purchased a grab-box of German and Soviet models from TradeMe (EBay equivalent in NZ) this week, collected it from the trader on Fiday. It turns out that he is as badly afflicted by Model Obsession as I am!

 And he also deals in models! Mostly Italeri. Everything from figures through armour. Mostly WW2 German, but some Italian and  Soviet too.

(I always smile at the term gun  "servants" on Italeri and Zvezda kits)

The grab-box contained the Nebelwerfers (mostly built) I was mostly after. (Think they may be Hasegawa Correction: ESCI kits); a number of 88 mm Flak guns some built, some unbuilt, a 25 pounder field gun and limber (No Tractor, though), 2 IS-2 Heavy tanks (Yay!) 2 x Zis 3 AT guns and crews, 10 (yes ten) built but not painted Panthers, 4 Tigers, a painted Puma armoured car, King Tiger and Panther. 

Unfortunately these are painted in Western Front Summer Camo, and won't fit with my Autumn themed armies, so out came the spray can last night, and they are already base-coated panzer grey. I am also still working on the Armourfast Jagdpanthers and Cromwells.


(More about the Nebelwerfers in a later post)

Further contents of the box turned out to be a wad of sprues with really useful bits on them, unbuilt Panther (I now have Panthers coming out my ears...) several Hasegawa German Infantry sets, a partly painted Russian Winter Infantry set, and, and...

Couldn't stop myself, and bought another 2 sets of ZIS-3  guns to make up a whole company of 6 guns and 2 more IS-2s, which will bring the number of these in my Tankovy up to 7 now.

Got all of the built models out on the bench last night, and resolved to get out the airbrush!

 As usual this also inspired me to look up the history of the ZIS gun:

The 76-mm divisional gun M1942 (ZiS-3) (Russian: 76-мм дивизионная пушка обр. 1942 г. (ЗиС-3)) was a Soviet 76.2 mm divisional field gun used during World War II. ZiS was a factory designation and stood for Zavod imeni Stalina ("factory named after Stalin"), the honorific title of Artillery Factory No. 92, which first constructed this gun.

The design of ZiS-3 started in the end of 1940 on the Artillery Factory No. 92 under supervision of V. G. Grabin, the chief designer of medium caliber Soviet guns. There was no order for this work; moreover, at this time the attitude toward such development programs on the part of artillery commanders, such as Marshal Kulik, the head officer of Soviet artillery, was extremely negative. 

The project was run purely on the initiative of Grabin, his design bureau and the Artillery Factory No. 92 head and his deputies. None of them informed state authorities (i.e. Marshal Kulik) about the ZiS-3 project.

The ZiS-3 was a combination of the light carriage from the 57 mm ZiS-2 anti-tank gun and a powerful 76.2 mm barrel from the previous divisional field gun F-22USV. In order to decrease the gun's recoil a muzzle brake was installed. This allowed the barrel to be mounted on a relatively light carriage without the risk of mechanical damage when firing. Many parts of the gun were cast, stamped or welded in order to reduce the amount of machine work. As a result, the amount of work required to construct a single ZiS-3 gun was three times less than that of the F-22USV gun. Furthermore, the cost to produce a ZiS-3 gun was only two thirds that of an F-22USV.

After having been built, the first ZiS-3 gun was hidden from the watchful eyes of state authorities, who continued to ignore the Red Army's need for light and medium field guns. The authorities' main argument was the information that German heavy tanks carried exceptionally strong armour. In reality Germany did not have such tanks in early 1941 and this misinformation was the result of successful Nazi propaganda.. Marshal Kulik had believed the propaganda and sent orders to stop the production of light 45 mm anti-tank guns and 76.2 mm divisional field guns.

Early in the war German tanks had weaker armour than was anticipated. Some were even vulnerable to large caliber DShK machine guns. Pre-war models of 76 mm divisional guns penetrated German vehicles with ease, but almost all these guns were lost in battles or captured by Germans in holding facilities. Some of them were later used against Soviet forces as different kinds of Panzerjaeger tank-hunter self-propelled guns. 

Tiger Tank and captured ZiS 3 guns late-war

Marshal Kulik ordered that mass production of 76.2 mm divisional field F-22USV guns be relaunched. Grabin and the head staff of Artillery Factory No. 92 decided to organize the mass production of ZiS-3 guns instead of F-22USVs. They succeeded, but ZiS-3 was not officially tested and adopted for Red Army service.

Red Army soldiers were in urgent need of these guns, the guns themselves were fine and numerous due to improved production technology, but all of them were in stock at Artillery Factory No. 92, since the military representatives refused to receive non-official guns. After some internal struggle between Grabin's team and military representatives, ZiS-3 guns were finally transferred to the Red Army under personal responsibility of Grabin and Artillery Factory No. 92 head staff.

Combat experience showed the superiority of ZiS-3 over all other types of divisional level field guns. This allowed the ZiS-3 to be presented to a group of state authorities headed by Joseph Stalin and thus obtain all the needed approval. After the demonstration was over Stalin said: "This gun is a masterpiece of artillery systems design." 

There was a five-day official state test run in February 1942. The result of this test was quite clear - ZiS-3 was adopted by the Red Army as divisional field gun model 1942 (full official name).

Grabin and his team soon begun to improve on the technology used in the ZiS-3 mass production. Artillery Factory No. 92 was equipped by conveyor assembly lines, which allowed the factory to produce ZiS-3 in even greater numbers with a low qualification workforce but without significant quality loss. Experienced laborers and engineers worked on complicated equipment and served as brigade leaders. Some of the young men who worked on Artillery Factory No. 92 were exempt from conscription. They learned the production process well and became high quality workers and engineers. This was yet another boost for the ZiS-3 production volume. As a result, at the end of World War II, ZiS-3 was the most numerous Soviet Army field gun. The total number of ZiS-3s produced exceeded 103,000 pieces.

Soviet soldiers liked ZiS-3 guns for their extreme reliability, durability, and accuracy. It was easy to maintain these guns and train novice crews with them. Light carriage allowed the ZiS-3 to be towed by trucks and heavy jeeps (such as the American lend-leased Dodge 3/4) or even hauled by the crew.

ZiS-3 had good anti-armour capabilities, it could knock out any German light and medium tank with its armour-piercing round. The appearance of the Tiger I and later the Panther, however, made the lives of ZiS-3 crews much harder, for their frontal armour was immune except for some small ballistic windows.

A battery of ZiS-3 consisted of four guns, with three batteries combined into a division, or battalion. Independent anti-tank regiments consisted of six batteries with no divisions. In addition to the gun batteries there was a staff battery which included a fire control section.

12 June 2013

Kapiti Wargames Club Open Day, Call for help from FoWers

Kapiti Wargaming Club Open Day:

  Call for Help from FoWers

Hi everyone. The Kapiti Wargames Club will be having an Open Day on Saturday 30 June 2013.
We hope to promote Wargaming regionally as a hobby and pastime as a whole, not just our club.

The event will be our second, with our first visit attracting well over a 100 visitors last year. 
(Infant steps yet) We plan to feature Warhammer Fantasy and 40K games, Flames of War in 20mm, Napoleonics/7-year war, and Starwars X-Wing games, and more

BUT we have run into a bit of difficulty finding members who are able to do a FoW Demo game in 15mm.

The date seems to clash with the FoW tournament schedule. :(

This is an appeal to regional FoW players not involved in the tournament. Would any of you be interested in doing a demo game on the day ? Any other period or scale is  of course also welcome. Just drop me a comment and we can discuss details.

9 June 2013

WW2 Curiosity photographs

Some WW2 Curiosity photographs

Hitler's shredded tweeds after the Wolfschanze blast (attempt on his life)

Stalin horsing around

Hitler delighted at the Volkswagen (Ferdinand Porsche, the designer at left)

Churchill (The First Sea Lord) emerging from the sea

Incoming over Moscow


Downed Kamikaze

Contrails and Fire in the sky
London Blitz

7 June 2013

Russki Tankovy: KV1 and IS-2 and ISU-122

Russian WW2 Tankovy for FoW 1/72

Building and painting my Russian Tanks for the Planned Armourgeddon Kursk Event at the Kapiti Wargames Club later this year, and also working on my D-Day and beyond Forces.

Jagdpanthers, Cromwells and ISU-122s in my workbench assmebly line

Jadgdpanthers and Cromwell kits from Armourfast, SU-122 from Italeri. The ISU-122s have the alternate barrels to build the ISU-152 variant too, but the instructions are pretty vague, and don't even mention the ISU-152

 Joseph (Iosef) Stalin 2 Tanks (Source Wikipedia)

Italeri models top and die-cast Altaya at bottom, weathered


The Iosif Stalin tank (IS, in Cyrillic "ИС" tanks, (meaning the Joseph Stalin tank) was a series of heavy tanks developed as a successor to the KV-series by the Soviet Union during World War II. The heavy tank was designed with thick armour to counter the German 88 mm guns, and carried a main gun that was capable of defeating the German Tiger and Panther tanks. It was mainly a breakthrough tank, firing a heavy high-explosive shell that was useful against entrenchments and bunkers. The IS-2 was put into service in April 1944, and was used as a spearhead in the Battle of Berlin by the Red Army in the final stage of the war.

KV1s (Altaya models, repainted and weathered)

KV and IS-1

The Kliment Voroshilov (KV) tanks were a series of Soviet Red Army heavy tanks, named after the Soviet defense commissar and politician Kliment Voroshilov. The KV series were known for their extremely heavy armour protection during the early part of World War II, especially during the first year of the invasion of the Soviet Union.

They were almost completely immune to the 3.7 cm KwK 36 and howitzer-like, short barreled 7.5 cm KwK 37 guns mounted respectively on the early Panzer III and Panzer IV tanks fielded by the invading German forces. Until better guns were developed by the Germans it was often the case that the only way to defeat a KV was with a point-blank shot to the rear.

Prior to the invasion, about 500 of the over 22,000 tanks then in Soviet service were of the KV-1 type. When the KV-1 appeared, it outclassed the French Char B1,the only other heavy tank in operational service in the world at that time. Yet in the end it turned out that there was little sense in producing the expensive KV tanks, as the T-34 medium tank performed better (or at least equally well) in all practical respects. Later in the war, the KV series became a base of development for the Josef Stalin (Iosif Stalin, or IS) series of tanks.

The KV series of Soviet heavy tanks was criticized by its crews for its poor mobility and lack of any heavier armament than the T-34 medium tank. In 1942 this problem was partially addressed by the lighter, faster KV-1S tank. The KV series were much more expensive than the T-34, without having greater combat performance; the heavy tank program was nearly cancelled by Stalin in 1943. However, the German employment of substantial numbers of Panther and Tiger tanks at the Battle of Kursk in 1943 changed Soviet priorities. In response, the Soviet tank industry created the stopgap KV-85, and embarked on the KV-13 design program to create a tank with more advanced armour layout and a more powerful main gun. The IS-85 (Object 237) prototype was initially accepted for production as the IS-1 heavy tank and first deliveries were made in October 1943. Production ended in January 1944.

The lighter KV-1S was released, with thinner armour and a smaller, lower turret in order to reclaim some speed. Importantly, the KV-1S also had a commander's cupola with all-around vision blocks, a first for a Soviet heavy tank. However, the thinning-out of the armor called into question why the tank was being produced at all, when the T-34 could seemingly do everything the KV could do and much more cheaply. The Soviet heavy tank program was close to cancellation in mid-1943.

The appearance of the German Panther tank in the summer of 1943 convinced the Red Army to make a serious upgrade of its tank force for the first time since 1941. Soviet tanks needed bigger guns to take on the growing numbers of Panthers and the few Tigers.

A stopgap upgrade to the KV series was the short-lived KV-85 or Objekt 239. This was a KV-1S with a new turret designed for the IS-85, mounting the same 85 mm D-5T gun as the SU-85 and early versions of the T-34-85; demand for the gun slowed production of the KV-85 tremendously and only 148 were built before the KV design was replaced. The KV-85 was produced in the fall and winter of 1943-44; they were sent to the front as of September 1943 and production of the KV-85 was stopped by the spring of 1944 once the IS-2 entered full scale production.


Gun choice
Two candidate weapons were the A-19 122 mm gun and the BS-3 100 mm gun. The BS-3 had superior armour penetration (185 mm compared to 160 mm), but a less useful high explosive round. Also, the BS-3 was a relatively new weapon in short supply, while there was excess production capacity for the A-19 and its ammunition. Compared to the older 76.2 mm tank gun, the A-19 had very good armour penetration, similar to that of the effective 75 mm high velocity gun mounted on the German Panther, and delivered 3.5 times the kinetic energy of the older F-34.

Out with the old and in with the new, IS2 passing the (unpopular) Churchill and Shermans, Stuarts

After testing both BS-3 and A-19 guns, the latter was selected as the main armament of the new tank, primarily because of its ready availability and the effect of its large high-explosive shell when attacking German fortifications. The A-19 used a separate shell and powder charge, resulting in a lower rate of fire and reduced ammunition capacity, both serious disadvantages in tank-to-tank engagements. The gun was very powerful, and while its 122 mm armour-piercing shell had a lower muzzle velocity than similar late-issue German 75 mm and 88 mm guns, Soviet proving-ground tests established that the A-19 could penetrate the front armour of the German Panther tank, and it was therefore considered adequate in the anti-tank role.

German Army data on the penetration ranges of the 122 mm A-19 gun against the Panther tank showed it to be much less effective when the Panther stood at a side angle of 30 degrees to the incoming round: the A-19 gun was unable to penetrate the glacis plate of the Panther at any distance, and could only penetrate the bottom front plate of the hull at 100 m. It was the large HE shell the gun fired which was its main asset, proving highly useful and destructive in the anti-personnel role. The size of its gun continued to plague the IS-2, and the two-piece ammunition was difficult to handle and slow to reload (the rate of fire was only about two rounds per minute). Another limitation imposed by the size of its ammunition was the payload: only 28 rounds could be carried inside the tank

The IS-122 prototype replaced the IS-85, and began mass production as the IS-2. The 85 mm guns could be reserved for the new T-34-85 medium tank, and some of the IS-1s built were rearmed before leaving the factory, and issued as IS-2s.
The main production model was the IS-2, with the powerful A-19. It was slightly lighter and faster than the heaviest KV model 1942 tank, with thicker front armour and a much-improved turret design. The tank could carry thicker armour than the KV series, while remaining lighter, due to the better layout of the armour envelope. The KV's armour was less well-shaped and featured heavy armour even on the rear, while the IS series concentrated its armour at the front. The IS-2 weighed about the same as a German Panther and was lighter than the German heavy Tiger tank series, and was slightly lower than either.
Western observers tended to criticize Soviet tanks for their lack of finish and crude construction. The Soviets responded that it was warranted considering the need for wartime expediency and the typically short battlefield life of their tanks.

Early IS-2s can be identified by the 'stepped' front hull casting with its small, opening driver's visor. The early tanks lacked gun tube travel locks or antiaircraft machine guns, and had narrow mantlets.

Later improved IS-2s (model 1944) had a faster-loading version of the gun, the D25-T with a double-baffle muzzle brake and better fire-control. It also featured a simpler hull front without a 'step' in it (using a flat, sloping glacis armour plate). Some sources called it IS-2m, but it is distinct from the official Soviet designation IS-2M for a 1950s modernization. Other minor upgrades included the addition of a travel lock on the hull rear, wider mantlet, and, on very late models, an antiaircraft machine gun.


Soviet High Command became interested in assault guns following the success of German Sturmgeschutz III SPGs. Assault guns had some advantages over tanks with turrets. The lack of a turret made them cheaper to produce. They could be built with a larger fighting compartment and could be fitted with bigger and more powerful weapons on a given chassis. However, assault guns could aim their cannons in high degree only by turning the entire vehicle, and were thus less suited for close combat than tanks with turrets.

The first SU-122s produced in December 1942 were sent to training centers and two new combat units, the 1433rd and 1434th self-propelled artillery regiments. Initially, each of these mixed regiments consisted of two batteries with four SU-122s each and four batteries with four SU-76 tank destroyers each. Each regiment had an additional SU-76 tank destroyer as a command vehicle. It was planned to raise 30 self-propelled artillery regiments operating within armoured and mechanized corps.

In January 1943, the 1433rd and 1434th self-propelled artillery regiments were sent to the Volkhov Front near Leningrad as part of the 54th Army. On 14 January they saw combat for the first time in Smierdny region. After that it was decided SU-122s should follow between 400 m and 600 m behind the attacking tanks; sometimes this distance was shortened to between 200 m and 300 m.

The use of SU-76 tank destroyers together with SU-122s proved unsuccessful. Based on combat experience, the organization of self-propelled artillery regiments was changed; the new regimental organization consisted of two batteries of SU-76 tank destroyers and three of SU-122s, for a total of 20 SPGs. In April the organization of self-propelled artillery regiments was again changed. Separate regiments were created for SU-76 tank destroyers (light self-propelled artillery regiment) and SU-122s (medium self-propelled artillery regiment).

The medium self-propelled artillery regiment consisted of four batteries of four SU-122s each. Each regiment was also equipped with either an additional SU-122 or a T-34 for the commander and a BA-64 armoured car. This organization remained in place until the beginning of 1944 when the SU-122 started to be replaced by the SU-152, ISU-122 and ISU-152 heavy SPGs and SU-85 tank destroyers.

The SU-122 proved effective in its intended role of direct fire on strongholds. The massive concussion of the 122mm HE round was reportedly enough to blow the turret off even a Tiger I if a direct hit was scored at close range, although longer range penetration against heavier German armor remained poor, a trait shared with the larger 152mm howitzers. The new BP-460A HEAT projectile was introduced in May 1943; however its primitive warhead design was only minimally more effective than brute concussive effects of the old HE shell at close range.

At least one SU-122 was captured by the German Army.


A prototype of the ISU-122 (in Russian ИСУ-122) heavy self-propelled gun was built at the Chelyabinsk Kirov Plant, (Chelyabinskiy Kirovskiy Zavod (ChKZ), Chelyabinsk, Russia), in December 1943. The design shared the chassis of the ISU-152 self-propelled gun and differed only in armament, having an A-19S 121.92-mm gun as its main weapon instead of the ISU-152's ML-20S gun-howitzer. Towed versions of these guns used the same carriage: 52-L-504A (Russian designation 52-Л-504А), so installation of an A-19 instead of an ML-20 gun was not a difficult task. After completing development of the ISU-152, ChKZ engineers mounted the A-19 gun on the ISU-152 chassis to create "Object 242" — the first ISU-122 prototype. It was successfully tested but not immediately launched into mass production.

At that time all ISU hulls were being equipped with the ML-20S gun-howitzer, but the production of hulls increased quickly and there was a lack of ML-20S tubes in the beginning of 1944. State authorities ordered these uncompleted hulls armed with an A-19 gun (specifically with the A-19S variant, slightly modified for the self-propelled gun mount). A further advantage of rearming the ISU was increased direct fire range against heavy German tanks. For these reasons the State Defense Committee adopted Object 242 for Red Army service as the ISU-122 on 12 March 1944. In April 1944 the first series ISU-122 left the ChKZ production lines.

The A-19S gun had a manual-piston breech, which reduced the rate of fire to 1.5 from 2.5 shots per minute. Soviet designers developed the D-25 by modernizing the A-19S's breech, creating a semi-automatic variant of the 121.92-mm gun. The D-25 gun was installed in IS-2 tanks as a priority, but in September 1944 became available for self-propelled guns. The prototype ISU vehicle, armed with a D-25S was designated "Object 249" and successfully passed plant and state testing. The fire rate was improved to 2 to 3 shots per minute and with two strong experienced loaders the rate of fire reached 4 shots per minute. Due to the muzzle brake reducing recoil forces the D-25 had a smaller recoil buffer than the A-19. This improved the crew's work conditions and allowed for a smaller, lighter gun shield with the same armour thickness.

After testing Object 249 was immediately launched in mass production as the ISU-122S (ИСУ-122С) self-propelled gun. However, the original ISU-122 remained in production (along with the ISU-152) due to a large stock of A-19 guns (the ML-20 and D-25 came directly from artillery factories). Mass production of the ISU-122 and ISU-122S ceased at the end of 1945. ChKZ produced 1,735 ISU-122 and 675 ISU-122S variants in total.

ISU 152