Weapon stories. ISU-122: the difficult path of a front-line soldier

2024 Author: Matthew Elmers | [email protected]. Last modified: 2023-12-16 21:49

Today we decided to talk about a car that cannot boast of participating in defensive battles. About the car, which, thanks to the "new historians of technology from Wikipedia", is often perceived as a simple assistant to the tank. A sort of ersatz tank, created for some unknown reason. But the car that took Berlin exactly! Although some features of the machine made its use in cities problematic.

So, the heroine today is ISU-122. ACS, which often stands next to ISU-152 and IS-2 tanks at museum expositions. And, let's be honest with ourselves, it undeservedly makes a less frightening impression than the neighbors. The impression is complemented by the fact that the ISU-122 looks like the ISU-152, and the cannon is exactly the same as on the IS-2 tank. Well, and a natural question: why bother with a machine that does not exceed the power of the prototype tank in terms of firepower?

In principle, in most of the previously described self-propelled guns of the USSR and Germany, this was exactly the case. SPGs were almost always equipped with a more powerful weapon. This is what provided artillery support for tank attacks. Self-propelled guns made it possible for tankers to reach the lines of effective operation of their own guns. Direct fire. To slip through the very area of the enemy's inaccessibility without significant losses.

Let's try to figure it out with this decision of the ACS designers.

But you need to start from afar. From the distant 1942. It was in 1942 that military experts of the Soviet Union, leading designers of armored vehicles, were tasked to think over the development trends of enemy tanks in the coming years. At the end of 1942, a special commission was even created at TsNII-48.

The conclusions on the development of the armored vehicles of the Germans were unambiguous. It is enough to cite a phrase from the report of the TsNII-48 commission (head professor, doctor of technical sciences A. S. Zavyalov):

Weapon stories. ISU-122: the difficult path of a front-line soldier

“During the war, we can expect the enemy to have new types of tanks, although the Germans, apparently, in every possible way avoid production complications associated with the transfer of industry to new models and affecting the mass production of weapons.

If such new samples appear, then it is unlikely that we will meet in them with the fact of a significant thickening of the armor.

Most likely, in accordance with the entire course of development of types of German tanks, one should expect an increase in tank artillery, on the one hand, and an increase in the cross-country ability of tanks in off-road conditions and powerful snow covers, on the other."

There is a fact that for some reason passed unnoticed by the Soviet command, but which could turn the design thought into a completely different plane. Experimental "Tigers" began to appear on the Soviet-German front in the fall-winter of 1942.

The historical fact of the capture of the Henschel type tank No. 250004 is known. It is the decoding of the waybill of this tank on January 25, 1943 (translator Bresker) that proves that this vehicle made its first raid on September 21, 1942 (reconnaissance in force at 10:30 in the area p. Mga-Gory). Why this remained unnoticed by the Soviet command is still unclear.

We specifically drew attention to what ideas were the main ones at the beginning of 1943. This will help to understand the logic behind the appearance of the ISU-122.

So, 1943. Tank builders are actively developing a new heavy tank IS-1. Two ACS were developed in parallel. The solution was classic. Tank with a 85 mm cannon (D-5T), tank fire support self-propelled guns (tank destroyer) with a 122 mm cannon (A-19) based on the KV-14 and self-propelled guns with a 152 mm howitzer cannon (ML-20S) on the same base.

Work on the creation of the tank was completed in November 1943. And already on the basis of the IS-1 was built ISU-152 (object 241). Next in line was object 242 with a 122 mm cannon. The prototype was built one month after Object 241.

And then the military intervened in the work. The fact is that the IS-1, with all its merits, no longer suited the gunners with its weapon. An 85 mm gun was clearly not enough for a heavy tank. The vehicle had no advantage in battle over other tanks. This gun was more suitable for the average T-34, which is what happened.

The gun intended for the self-propelled guns was installed on a new development of the tank - object 240 (IS-2). It so happened that object 240 (IS-2) came out for testing even earlier than object 241 (ISU-152). Object 242 thus became unnecessary. Precisely because of the same type of gun with a tank. ISU-152 went into production. In practice, from December 1943 to April 1944, ChTZ produced only the ISU-152.

And again, chance helped. More precisely, the labor exploits of the workers of ChTZ. The plant produced armored hulls for self-propelled guns in large quantities. By April, it turned out that there was simply not enough ML-20S guns for the production of the ISU-152 self-propelled guns. And at the same time, a sufficient number of tank A-19s accumulated in the warehouses (since the beginning of production of the IS-2, it was named D-25T).

Chelyabinsk Tractor began to produce two SPGs at once: ISU-152 and ISU-122. But this is not the end of the history of this car. It was a successful sequel! And we can see this continuation today too. This is the ISU-122S. This is not a whim of restless ACS designers, but a necessity.

The tasks that the SPGs should perform even with the same guns as the tanks have not been canceled. On the SU-122, the designers were able to achieve some increase in the rate of fire (from 2 to 3 rounds per minute) due to the freer cabin and the fifth crew member. But the weapon itself could not give out more. The piston valve interfered.

Artillery designers set about improving the shutter. And already at the end of 1943, the gun received a semi-automatic wedge breechblock. The gun was named D-25S. It was installed on the IS-2 almost immediately. There were no such weapons for the ISU-122.

But in the second half of 1944, the designers still managed to create a new prototype - object 249. The machine even externally differed from the ISU-122. The new gun was equipped with a muzzle brake. The mask has become more compact due to the decrease in the recoil devices of the gun. By the way, this reduction made it possible to increase the gun traverse angle.

I liked the car. I liked it so much that already in September 1944, ChTZ began to produce three production cars at once! ISU-152, ISU-122 and ISU-122S!

We pass on to inspect the car in detail. First of all, it must be said that this is a classic Soviet car of that time. The control compartment and the fighting compartment are located in front. Transmission and rear engine compartment.

The hull was made of rolled armor of various thicknesses: 90, 75, 60, 30 and 20 mm. Armor plates were installed at rational angles of inclination. In general, this reservation provided good anti-cannon protection. The forehead of cars of different production times was armored in different ways. The first vehicles had armor casting. Later - welded forehead.

The gun is not located along the centerline of the hull, but slightly shifted to the right of the axis of the vehicle. It was installed on a frame-type installation, almost identical to the ISU-152. The recoil devices are protected by a fixed cast casing and a movable cast mask. By the way, the mask, in addition to its main function, plays the role of a balancing device.

The crew was placed as follows. The driver is in front, on the left. Behind him, to the left of the gun, was the gunner. To the right of the gun is the commander. The loader's place is behind the gunner. Behind the commander is the seat of the castle. Sometimes the crews were formed of 4 people. In this case, the castle also performed the duties of a loader.

There were two hatches on the roof of the wheelhouse. But only the right one was intended for embarkation and disembarkation. The left hatch is intended for the extension of the panoramic sight. The main hatch for embarkation and disembarkation of the crew was a rectangular double-leaf hatch at the junction of the roof and rear sheets of the armored cabin.

Provided in the ISU and an emergency hatch for evacuation of the crew. Located at the bottom of the car. The rest of the hatches are designed for access to the components and assemblies of the machine, refueling and ammunition.

The ISU-122 used the A-19S guns. Moreover, the guns were different. The first vehicles are equipped with a 122-mm cannon mod. 1931/37 Modification C concerned the transfer of gun controls to one side for ease of guidance, equipping its breech with a receiver tray for easy loading and installation of an electric trigger. Piston bolt, identical to the towed gun.

Since May 1944, a 122-mm self-propelled gun mod. 1931/44 The barrel of this gun was already different from the A-19.

The following types of ammunition are used to fire the A-19 or D-25S cannons:

- high-explosive fragmentation cannon grenade OF-471N with a screwed head;

- high-explosive fragmentation all-hull short cannon grenade OF-471N;

- high-explosive fragmentation all-hull long cannon grenade OF-471;

- high-explosive high-explosive steel howitzer grenade OF-462;

- armor-piercing tracer sharp-headed projectile BR-471;

- armor-piercing tracer with a ballistic tip BR-471B;

- concrete-piercing cannon shell G-471.

To fire on the ACS, two devices were installed at once: a Hertz panorama and a ST-18 telescopic sight (for direct fire).

True, it should be said that the ST-18 device somewhat reduced the firing range. The fact is that the device was calibrated for only 1500 meters. Therefore, it was impossible to use it for longer distances. The panorama of Hertz saved.

The crew, in addition to aiming devices, had enough observation devices. All landing and disembarkation hatches were equipped with Mk IV periscopes.

Now, according to the logic of the material, it is necessary to talk about the chassis, engine compartment, chassis. However, today we decided not to. Simply because they described all this in sufficient detail in the materials about the IS-2 tank.

Therefore, the next part will be about the combat use of the vehicle. Let's start with one fairly well-known interview given to the front-line correspondent by the commander of the 309th SAP Lieutenant Colonel Kobrin. Just to quote an excerpt from this material:

"… Imagine this picture … As I remember now: height 559, 6. Commander Rybalko is with us. Klimenkov's self-propelled gun is right there - guarding the headquarters. There is a business conversation. And suddenly there are German tanks on the left. Eighteen of them! They are going in a column …" What will happen?

Rybalko's face changed a little - there were nodules on his cheeks. Commanding Klimenkov, who was standing nearby: "Deny the way for German tanks with fire!" - "There is a ban!" - Klimenkov answers and - to the car.

And what do you think? The first shell from one thousand eight hundred meters lit the lead tank, the second began to crawl out because of it - he knocked it out, the third climbed - he broke it, and then the fourth … He stopped the Nazis, they backed away, thinking that there was a whole battery …

Incredible? Meet Rybalko, ask him how it was, he will confirm. Then, right there, on the battlefield, Klimenkov was screwed to his overalls with the Order of the Patriotic War of the first degree …"

Now there is bound to be a skeptic who will talk about the personal courage and preparedness of the crew. Is this an indicator of the quality of the car? Let's say right away - yes, this is an indicator of the quality of the car.

The ISU-122, at the beginning of their use in the troops, had practically the same task as the ISU-152. The tactics of combat use were identical. But what is good on paper does not mean good in life.

Remember the soldier's nickname "St. John's Wort", which was received by the ISU-152 self-propelled guns? I got it deservedly. The Nazis did not have cars that could withstand the hit of a shell from the ML-20. But the problem was not the power of the gun, but the very possibility of hitting the tank. The short barrel did not give a guaranteed hit.

The ISU-122 had a gun with a longer barrel. And the number of shells in this self-propelled gun was one and a half times more. Even a fairly light projectile, compared to a 152-mm one, with an appropriate initial velocity of the shot, had not only penetrating, but also a huge stopping effect.

Even "Elephanta" stopped from the impact of the ISU-122 shell! They stopped not from breaking through the armor, which, alas, the 122-mm guns could not, but from the fact that after the impact the suspension, transmission or engine broke down. By the way, for statistics lovers. The data that are cited in various sources on the booking of German heavy vehicles at the end of the war, do not take into account one important detail. The armor of the Germans in the 45th and 43rd years varied greatly in quality.

But back to Lieutenant Klimenkov. Klimenkov offered nothing new in battle tactics. The actions of the ISU-122 from ambushes at a great distance were provided for by the establishing documents of the Red Army. Another thing is that the car worked on the Hertz panorama, judging by the range.

To be objective, the IS-2 and ISU-122 at that time were the only machines equivalent to the Germans. Only they could destroy German heavy tanks and self-propelled guns at a distance of battle.

Remember the dispute between the commander of the SU-85 and the tank colonel from the movie "In War as in War"? About the place of the ACS in the battle formations of the attacking ones? 200-300 meters behind the tanks. The same applies to the ISU-122. The vehicles simply shot at enemy tanks from short stops.

It is quite another matter when the attack was choking and the tanks began to retreat. This is where the heroism of the self-propelled gunners manifested itself. The self-propelled guns became just long-range guns, which destroyed the advancing tanks or those objects that made further advance difficult with direct fire. Withdrawal (or continuation of the offensive) in this case was carried out after the danger of losing tanks had passed.

I would like to tell you about one more episode of the war. More precisely, about a small war of one tank regiment. Yes, it’s a tank! 81st separate guards heavy tank regiment. The war, which took 12 days in March 1945 … We wrote many times about the miracles in the war. Today is the miracle of instant retraining.

On March 8, 81 OGvTTP received 20 ISU-122 from four marching batteries (at that time 1 serviceable IS-2 tank remained in it) and entered into battle with the enemy surrounded in the area south-west of Konigsberg. For 12 days of fighting, the regiment lost 7 officers and 8 soldiers killed, 11 officers and 13 soldiers and sergeants wounded. During the battles, 10 ISU-122s burned down and 5 more were damaged.

Tankers, having retrained in self-propelled guns, captured the settlements of Eisenberg, Waltersdorf, Birknau, Grunau and reached the Baltic Sea coast. The regiment destroyed 5 tanks, 3 assault guns, 65 anti-tank guns, 8 armored personnel carriers, 9 tractors and captured 18 guns and one Panther in good order. The regiment remained a tank regiment!

And one more battle of the Hero of the Soviet Union V. Gushchin, who fought in the 387 SAP on the battle on January 20, 1945. And again, just quoting. You can't write better anyway:

“The first city, Inoros, was especially strongly fortified. Our attempts to break into the city did not lead to success. joy and pride in the responsibility entrusted to us.

We started to do it. At that time there was a heavy fog, therefore visibility was very poor. Our battalion commander and crew members had to open hatches in order to better see where the enemy was. At the approach to the city there was a small farm. When we approached the farm, the enemy suddenly opened fire on us, as a result of which the battalion commander of the lead vehicle was killed, and the second vehicle was damaged.

After that I take command. I order to fire several shots at this fortified farm, after which, making sure that the enemy has been destroyed, I decided to break into the city.

As I approached, I saw German tanks on the right and on the left … I make an immediate decision - to retreat to cover, and then engage the enemy. He also took the second car with him.

The first car, in which I was, parked on the left, in the direction of the enemy. And I parked the second car on the right side. Not having been in this position for an hour, I saw that the German tanks were walking along the road two hundred meters away. At that moment, I opened fire on them. The first shell hit the front of the tank. The tank did not catch fire. Having let him go 100 meters, he opened fire on him again. From the second round, the tank caught fire. The Germans began to run out of the tank and scatter in different directions.

Wasting no time, I switch fire to other tanks. They walked one after another. The second tank also caught fire, then the third. The fourth tank noticed us and began to direct fire at me. I immediately give the order: "Full throttle, aside!" And as soon as I had time to drive away, they started shooting at the place where I was standing. Using this time, I immediately direct fire on the next tank and burn it. And in the same way I knocked out 8 German tanks …"

Well, the traditional performance characteristics of the heroine, ISU-122: