By the beginning of 1943, an alarming situation for our command had developed on the Soviet-German front. According to reports coming from the tank units of the Red Army, the enemy began to massively use tanks and self-propelled guns, which, in terms of the characteristics of weapons and security, began to surpass our most massive T-34 medium tanks. This primarily applied to the modernized German Pz. KpfW. IV Ausf. F2 medium tanks and the StuG III Ausf self-propelled guns. F. Frontal armor with a thickness of 80 mm, long-barreled 75-mm guns, combined with excellent optics and well-trained crews, allowed German tankers to more often emerge victorious in tank duels under equal conditions. In addition, the enemy's anti-tank artillery became more and more saturated with 7, 5 cm Pak guns. 40. All this led to the fact that the Soviet T-34 and KV ceased to dominate the battlefield. The situation became even more alarming after it became known about the creation of new heavy tanks in Germany.
After the defeat of the Germans at Stalingrad and the transition of Soviet troops to the offensive, the loss of quality superiority in armored vehicles of the USSR was largely compensated for by the ever-increasing production of tanks and the growth of the operational skill of the Soviet command, advanced training and skills of personnel. In late 1942 - early 1943, Soviet tank crews no longer suffered such catastrophic losses as in the initial period of the war. As the German generals complained: "We taught the Russians to fight on our own heads."
After the seizure of the strategic initiative in the conditions of offensive hostilities, the armored units of the Red Army needed qualitatively new models of equipment. Taking into account the existing operating experience of the SU-76M and SU-122, self-propelled assault artillery mounts were developed, armed with large-caliber howitzers, designed to destroy fortifications when breaking through enemy defenses, and anti-tank self-propelled guns with guns created on the basis of anti-aircraft and sea guns.
During the planned offensive operations of 1943, it was expected that Soviet troops would have to break into long-term defense in depth with concrete pillboxes. The Red Army needed a heavy self-propelled gun with weapons similar to the KV-2. However, by that time, the production of 152 mm M-10 howitzers had been discontinued, and the KV-2s themselves, which had not proved themselves too well, were all lost in the battles. The designers came to understand that from the point of view of obtaining optimal weight and size characteristics, placing a large-caliber gun on a combat vehicle in an armored wheelhouse is more preferable than in a turret. The abandonment of the rotating turret made it possible to increase the habitable volumes, save weight and reduce the cost of the car.
In February 1943, ChKZ began serial production of the SU-152. As follows from the designation, the self-propelled gun was armed with a 152-mm ML-20S - a tank modification of a very successful 152-mm howitzer-gun mod. 1937 (ML-20). This gun was located in a niche between long-barreled cannons of special power and classic field howitzers with a short barrel, greatly outperforming the former in terms of mass and in firing range of the latter. The SU-152 gun had a horizontal firing sector of 12 ° and elevation angles of −5 - + 18 °. The rate of fire in practice did not exceed 1-2 rds / min. The ammunition consisted of 20 rounds of separate-case loading. Theoretically, all types of ML-20 cannon shells could be used in the ACS, but mostly they were high-explosive fragmentation shells. The range of direct fire was 3, 8 km, the maximum firing range from closed positions was 6, 2 km. But shooting from closed positions, for a number of reasons, which will be discussed below, was very rarely practiced by self-propelled guns.
SU-152
The base for the SPG was the KV-1S heavy tank, while the SU-152 was almost the same as the tank in terms of protection. The thickness of the frontal armor of the cabin was 75 mm, the forehead of the hull was 60 mm, the side of the hull and the cabin was 60 mm. The combat weight of the vehicle is 45.5 tons, the crew is 5 people, including two loaders. The introduction of two loaders was due to the fact that the weight of the high-explosive fragmentation projectile exceeded 40 kg.
Serial production of the SU-152 ACS continued until December 1943 and ended simultaneously with the termination of production of the KV-1S tank. The number of SU-152 built in different sources is indicated in different ways, but most often the figure is 670 copies.
The most active self-propelled guns were used at the front in the period from the second half of 1943 to mid-1944. After the termination of production of the KV-1S ACS SU-152, the units based on the IS heavy tank were replaced in the army. Compared to tanks, the SU-152 self-propelled guns suffered less losses from anti-tank artillery fire and enemy tanks, and therefore many heavy self-propelled guns were written off due to the depletion of a resource. But some of the vehicles that underwent refurbishment took part in the hostilities before the surrender of Germany.
The first SU-152s entered the army in May 1943. Two heavy self-propelled artillery regiments of 12 self-propelled guns in each took part in the battle near Kursk. Contrary to widespread myths, due to their small number, they did not have much influence on the course of hostilities there. During the battle on the Kursk Bulge, self-propelled guns, as a rule, were used for firing from closed firing positions, and, moving behind the tanks, provided them with fire support. Due to the fact that there were few direct clashes with German tanks, the losses of the SU-152 were minimal. However, there were also cases of direct fire at enemy tanks.
Here is what the combat summary for July 8, 1943 of the 1529th TSAP, which was part of the 7th Guards Army of the Voronezh Front, says:
“During the day, the regiment fired: 1943-08-07 at 16.00 at the battery of assault guns on the southern outskirts of the farm. "Polyana". 7 self-propelled guns were knocked out and burned and 2 bunkers were destroyed, consumption of 12 HE grenades. At 17.00 on enemy tanks (up to 10 units), which entered the grader road 2 km south-west of the farm. "Batratskaya Dacha". Direct fire of the SU-152 of the 3rd battery, 2 tanks were lit and 2 knocked out, one of them T-6. Consumption of 15 RP grenades. At 18.00, the commander of the 7th Guards visited the 3rd battery. army, Lieutenant General Shumilov and expressed gratitude to the calculations for excellent shooting at tanks. At 19.00, a convoy of vehicles and carts with infantry on the road south of the farm was fired upon. "Polyana", 2 cars, 6 carts with infantry were wrecked. Up to the infantry company scattered and partially destroyed. Consumption of 6 RP grenades ".
Based on the above combat summary, two conclusions can be drawn. Firstly, it should be noted the good shooting performance and low consumption of projectiles: for example, in the first combat episode, 12 high-explosive fragmentation grenades hit 9 targets. Secondly, based on other combat episodes, it can be assumed that the enemy, having come under fire from powerful guns, retreated faster than the crews of the self-propelled guns had time to completely destroy him. Otherwise, the consumption of projectiles could be significantly higher. Which, however, does not detract from the combat value of heavy self-propelled guns.
In reports on the results of hostilities among the armored vehicles destroyed by the crews of the SU-152, heavy tanks "Tiger" and PT ACS "Ferdinand" repeatedly appear. In fairness, it should be said that firing even a 152-mm high-explosive fragmentation projectile at German tanks gave a very good result, and a direct hit was not always required to disable enemy armored vehicles. As a result of a close rupture, the chassis was damaged, observation devices and weapons were knocked out, the tower was jammed. Among our soldiers, the SU-152 self-propelled guns have earned a proud name - "St. John's Wort". Another question is how much it was really deserved. Of course, the armor of any German tank could not withstand the hit of an armor-piercing shell fired from a 152-mm howitzer cannon. But, given that the ML-20 direct shot range was about 800 meters, and the rate of fire at best did not exceed 2 rounds / min, the SU-152 could successfully operate against medium and heavy tanks armed with long-barreled guns with a high rate of fire, only from an ambush.
The number of destroyed "Tigers", "Panthers" and "Ferdinads" in the reports of military operations and in the memoir literature is many times greater than the number of these machines, built at factories in Germany. "Tigers", as a rule, were called shielded "fours", and "Ferdinands" all German self-propelled guns.
After the capture of the German tank Pz. Kpfw. VI "Tiger" in the USSR began hastily to create tanks and self-propelled guns, armed with weapons capable of fighting heavy enemy tanks. Tests at the proving ground have shown that an 85-mm anti-aircraft gun can cope with the Tiger's armor at medium distances. Designer F. F. Petrov created an 85 mm D-5 tank gun with anti-aircraft gun ballistic data. The D-5S variant was armed with the SU-85 tank destroyer. The elevation angles of the gun were from −5 ° to + 25 °, the horizontal firing sector was ± 10 °. Direct fire range - 3, 8 km, maximum firing range - 12, 7 km. Thanks to the use of unitary loading shots, the rate of fire was 5-6 rds / min. The ammunition load of the SU-85 contained 48 rounds.
SU-85
The vehicle was created on the basis of the SU-122, the main differences were mainly in the armament. Production of the SU-85 began in July 1943, and the self-propelled gun did not have time to take part in the battles at the Kursk Bulge. Thanks to the use of the SU-122 hull, well-developed in production, it was possible to quickly establish mass production of the SU-85 anti-tank self-propelled guns. In terms of security, the SU-85, like the SU-122, was at the level of the T-34 medium tank, the armor thickness of the tank destroyer did not exceed 45 mm, which was clearly not enough for the second half of 1943.
ACS SU-85 entered separate self-propelled artillery regiments (SAP). The regiment had four batteries with four installations each. SAP was used as part of anti-tank artillery fighter brigades as a mobile reserve or attached to rifle units to enhance their anti-tank capabilities, where infantry commanders were often used as line tanks.
Compared to the 85-mm 52-K anti-aircraft gun, the range of ammunition in the ACS ammunition was much higher. O-365 fragmentation grenades weighing 9, 54 kg, after setting the fuse to high-explosive action, could be successfully used against enemy fortifications. An armor-piercing tracer projectile with a ballistic tip 53-BR-365 weighing 9.2 kg, with an initial speed of 792 m / s at a distance of 500 meters along the normal, pierced 105 mm armor. This made it possible to confidently hit the most common late-modification Pz. IV medium German tanks at all real combat distances. If you do not take into account the Soviet heavy tanks KV-85 and IS-1, of which few were built, before the appearance of the T-34-85 tanks, only the SU-85 self-propelled guns could effectively fight enemy medium tanks at distances of more than a kilometer.
However, already the first months of combat use of the SU-85 demonstrated that the power of an 85-mm gun is not always sufficient to effectively counter the enemy's heavy tanks "Panther" and "Tiger", which, possessing effective aiming systems and an advantage in defenses, imposed combat from long distances … To combat heavy tanks, the BR-365P sub-caliber projectile was well suited; at a distance of 500 m along the normal, it pierced armor with a thickness of 140 mm. But subcaliber projectiles were effective at relatively short distances, with an increase in range, their armor penetration characteristics fell sharply.
Despite some shortcomings, the SU-85 was loved in the army, and this self-propelled gun was in great demand. A significant advantage of the self-propelled guns in comparison with the later T-34-85 tank, armed with a gun of the same caliber, was the better working conditions for the gunner and loader in the conning tower, which was more spacious than the tank turret. This reduced the fatigue of the crew and increased the practical rate of fire and accuracy of fire.
Unlike the SU-122 and SU-152, the anti-tank SU-85s, as a rule, operated in the same battle formations together with tanks, and therefore their losses were very significant. From July 1943 to November 1944, 2652 military vehicles were accepted from the industry, which were successfully used until the end of the war.
In 1968, based on the story of the writer V. A. Kurochkin "In War as in War" about the commander and the crew of the SU-85, a wonderful film of the same name was shot. Due to the fact that all the SU-85s had been decommissioned by that time, the SU-100 played its role, of which there were still many in the Soviet army at that time.
On November 6, 1943, by a decree of the State Defense Committee, the ISU-152 heavy assault self-propelled gun, created on the basis of the Joseph Stalin heavy tank, was adopted. In production, the ISU-152 replaced the SU-152 based on the KV tank. The armament of the self-propelled gun remained the same -152, 4-mm howitzer-gun ML-20S mod. 1937/43 The gun was guided in a vertical plane in the range from −3 to + 20 °, the horizontal guidance sector was 10 °. The range of a direct shot at a target with a height of 2.5 m is 800 m, the range of direct fire is 3800 m. The real rate of fire is 1-2 rds / min. Ammunition was 21 rounds of separate-case loading. The number of crew members remained the same as in the SU-152 - 5 people.
ISU-152
Compared to its predecessor, the SU-152, the new SPG was much better protected. The most widespread in the second half of the war was the German 75-mm Pak 40 anti-tank gun and the Pz. IV at distances over 800 m could not penetrate the frontal 90 mm armor, which had a slope of 30 °, with an armor-piercing projectile. The living conditions of the ISU-152 fighting compartment have become better, the work of the crew has become somewhat easier. After identifying and eliminating "childhood diseases", the self-propelled gun demonstrated unpretentiousness in maintenance and a fairly high level of technical reliability, surpassing the SU-152 in this respect. The ISU-152 was quite maintainable, often the self-propelled guns that received combat damage were returned to service a few days after being repaired in the field workshops.
The mobility of the ISU-152 on the ground was the same as that of the IS-2. The reference literature indicates that the self-propelled gun on the highway could move at a speed of 40 km / h, while the maximum speed of a heavy tank IS-2, weighing the same 46 tons, is only 37 km / h. In reality, heavy tanks and self-propelled guns moved on paved roads at a speed of no more than 25 km / h, and over rough terrain 5-7 km / h.
The main purpose of the ISU-152 at the front was fire support for the advancing tank and infantry subunits. 152, 4-mm HE-540 high-explosive projectile weighing 43, 56 kg, containing about 6 kg of TNT with a fuse for fragmentation action, was very effective against naked infantry, with the installation of a fuse for high-explosive action against bunkers, bunkers, dugouts, armored caps and capital brick buildings. One hit of a projectile fired from an ML-20S gun into a three-four-storey medium-sized city house was often enough to destroy all living things inside. ISU-152 were especially in demand during the assault on the city blocks of Berlin and Königsberg, turned into fortified areas.
Heavy SPG ISU-152 inherited the nickname "St. John's Wort" from its predecessor. But in this field, the heavy assault self-propelled gun was significantly inferior to the specialized tank destroyer, armed with guns with high ballistics and a combat rate of fire of 6-8 rds / min. As already mentioned, the direct firing range of the ISU-152 gun did not exceed 800 meters, and the rate of fire was only 1-2 rounds / min. At a distance of 1,500 meters, an armor-piercing projectile of the 75-mm KwK 42 gun of the German Panther tank with a barrel length of 70 calibers pierced the frontal armor of a Soviet self-propelled gun. Despite the fact that German tankers could respond to 1-2 Soviet 152-mm projectiles with six aimed shots, it was, to put it mildly, not reasonable to engage in direct battles with heavy enemy tanks at medium and long distances. By the end of the war, Soviet tankers and self-propelled gunners learned how to correctly select positions for anti-tank ambushes, acting for sure. Careful camouflage and quick change of firing positions helped to achieve success. In the offensive, the low rate of fire of 152-mm guns was usually compensated for by the coordinated actions of a group of 4-5 self-propelled guns. In this case, in a head-on collision, the few German tanks by that time had practically no chances. According to archival data, from November 1943 to May 1945, 1,885 self-propelled guns were built, the production of the ISU-152 ended in 1946.
In 1944, the production of the ISU-152 was largely constrained by the shortage of ML-20S guns. In April 1944, the serial assembly of the ISU-122 self-propelled guns began, which were armed with a 122-mm A-19S cannon with a barrel length of 48 calibers. These weapons were in abundance in the warehouses of art weapons. Initially, the A-19C gun had a piston-type breechblock, which significantly limited the rate of fire (1, 5-2, 5 rounds per minute). The self-propelled gun had 30 rounds of separate-case loading. As a rule, these were 25 high-explosive and 5 armor-piercing shells. This ratio of ammunition reflected what targets the self-propelled guns often had to fire at.
ISU-122
In the fall of 1944, the ISU-122S self-propelled gun was launched into the series with a 122-mm self-propelled version of the D-25S cannon, equipped with a semi-automatic wedge gate. The rate of fire of the D-25S reached 4 rds / min. According to this indicator, the self-propelled gun, due to the better working conditions of the loaders and the more spacious layout of the fighting compartment, surpassed the heavy tank IS-2, which was armed with almost the same D-25T gun. Visually, the ISU-122 differed from the ISU-152 in a longer and thinner gun barrel.
The ISU-122S turned out to be even more versatile and in demand compared to the ISU-152. A good rate of fire, a high range of a direct shot and a great power of the projectile's action made it equally effective both as a means of artillery support and as a highly effective tank destroyer. At the front, there was a kind of "division of labor" between ISU-152 and ISU-122. Self-propelled guns with a 152-mm gun were used as assault guns, operating in cities and on tight roads. The ISU-122, with its longer gun, was difficult to maneuver on the streets. They were more often used when breaking through fortified positions in open areas and for firing from closed positions in the absence of towed artillery during rapid breakthroughs, when the towed guns did not have time to advance behind the tank and mechanized units of the Red Army. In this role, the large firing range exceeding 14 km was especially valuable.
ISU-122S
The characteristics of the ISU-122S gun made it possible to fight against heavy enemy tanks at all available combat distances. The 25-kg armor-piercing projectile BR-471, leaving the barrel of the D-25S gun with an initial speed of 800 m / s, penetrated the armor of any German armored vehicle, with the exception of the Ferdinand tank destroyer. However, the impact on the frontal armor did not pass without leaving a trace for the German self-propelled gun. Chips occurred from the inner surface of the armor, and mechanisms and assemblies failed from a powerful shock. High-explosive steel grenades OF-471 and OF-471N also had a good striking effect on armored targets when the fuse was set to high-explosive action. A kinetic blow and subsequent explosion of 3, 6-3, 8 kg of TNT, as a rule, was enough to disable a heavy enemy tank even without breaking through the armor.
ISU-122 of all modifications was actively used at the final stage of the war as a powerful tank destroyer and assault ACS, having played a large role in the defeat of Germany and its satellites. In total, Soviet industry supplied 1,735 self-propelled guns of this type to the troops.
Talking about Soviet self-propelled guns with 122-152-mm guns, it can be noted that, despite the available opportunity, they rarely fired from closed positions. This was mainly due to the lack of training of the self-propelled guns crews to conduct effective fire from closed positions, the insufficient number of trained spotters, and the lack of communications and topographic reference. An important factor was the consumption of shells. The Soviet command believed that it was easier and more profitable to complete a combat mission with direct fire, firing several 152-mm shells, albeit with the risk of losing a car and crew, than wasting hundreds of shells with an unobvious result. All these factors became the reason that during the war years all our heavy self-propelled artillery units were created for direct fire, that is, they were assault.
Insufficient security and not always satisfying the military power of the armament of the tank destroyer ACS SU-85 were the reason for the creation of a self-propelled gun with a 100-mm unitary loading gun. The self-propelled unit, designated SU-100, was created by the designers of Uralmashzavod in 1944.
The results of the shelling of captured German tanks at the range demonstrated the low effectiveness of 85-mm shells against the high-hardness German armor installed at rational angles of inclination. Tests have shown that for a confident defeat of heavy German tanks and self-propelled guns, a gun with a caliber of at least 100 mm was required. In this regard, it was decided to create a tank gun using unitary shots of the 100-mm universal naval gun with high ballistics B-34. At the same time, a new SPG hull was designed on the chassis of the T-34 medium tank. The thickness of the upper part of the frontal armor, the most vulnerable from the point of view of the probability of hitting shells, was 75 mm, the angle of inclination of the frontal plate was 50 °, which in terms of ballistic resistance exceeded the 100 mm armor plate installed vertically. The significantly increased protection compared to the SU-85 made it possible to confidently resist the hits of shells from 75 mm anti-tank and medium tanks Pz. IV. In addition, the SU-100 had a low silhouette, which significantly reduced the likelihood of hitting it and made it easier to camouflage when in cover. Thanks to the sufficiently developed base of the T-34 tank, self-propelled guns, after the start of deliveries to the troops, had almost no complaints about the level of reliability, their repair and restoration in the conditions of front-line tank repair workshops did not cause difficulties.
Based on combat experience and taking into account the many wishes of Soviet tankers and self-propelled gunners, a commander's cupola was introduced on the SU-100, similar to that used on the T-34-85. The view from the turret was provided by the MK-4 periscope observation device. Along the perimeter of the commander's cupola, there were five viewing slots with quick-change protective triplex glass blocks. The presence of a fairly good view of the battlefield from the commander of the ACS made it possible to detect targets in a timely manner and control the actions of the gunner and driver.
SU-100
When designing the SU-100, initially, some attention was paid to the ergonomics and habitability conditions in the fighting compartment of the new self-propelled gun, which was uncharacteristic for domestic tank building during the war years. Although, of course, the level of comfort inherent in the armored vehicles of the allies and, in part, the Germans, was not achieved for the four crew members, and the situation inside the self-propelled gun was Spartan. Soviet self-propelled guns SU-100 were very fond of and the transfer to other equipment was perceived as a punishment.
The combat weight of the SU-100 due to the abandonment of the turret, even with better protection and a larger caliber gun, was about half a ton less than that of the T-34-85 tank, which had a beneficial effect on mobility and maneuverability. However, self-propelled gunners had to be very careful when driving over very rough terrain, so as not to "scoop" the ground with a relatively low-lying long-barreled gun. Also for this reason, it was difficult to maneuver in the narrow streets of European cities.
In preparation for the start of serial production of the SU-100, it turned out that the supply of SPGs to the troops was hampered by the insufficient number of available 100-mm guns. In addition, the enterprises of the People's Commissariat of Ammunition did not manage to timely organize the production of 100-mm armor-piercing shells. In this situation, as a temporary measure, it was decided to install 85-mm D-5S guns on the new self-propelled guns. The self-propelled gun with an 85-mm cannon in the new corps received the designation SU-85M. In 1944, 315 such installations were built.
ACS SU-100 was armed with a 100-mm cannon D-10S mod. 1944 with a barrel length of 56 calibers. In the vertical plane, the gun was guided in the range from −3 to + 20 °, and in the horizontal plane - 16 °. The D-10S cannon, which proved to be extremely powerful and effective, could fight all types of enemy heavy armored vehicles. In the post-war period, the T-54 and T-55 tanks were armed with tank versions of the D-10T gun, which are still in operation in many countries.
The range of a direct shot with an armor-piercing projectile 53-BR-412 at a target 2 meters high was 1040 meters. At a distance of 1000 meters, this shell, which weighed 15, 88 kg, penetrated 135 mm armor along the normal. The HE-412 high-explosive fragmentation projectile weighing 15, 60 kg contained 1.5 kg of TNT, which made it an effective means of destroying field fortifications and destroying enemy manpower. The SU-100 ammunition contained 33 unitary loading rounds. Usually the ratio of high-explosive and armor-piercing shells was 3: 1. Combat rate of fire with the coordinated work of the gunner and loader reached 5-6 rds / min.
From September 1944 to May 1945, about 1,500 SU-100s were transferred to the troops. The enemy very quickly appreciated the security and firepower of the new Soviet self-propelled guns, and German tanks began to avoid head-on collisions with them. Squat and mobile self-propelled guns with 100-mm guns, due to their higher rate of fire and long range of direct fire, were even more dangerous opponents than heavy IS-2 tanks and self-propelled guns with 122 and 152 mm guns. The closest German analogue of the SU-100 in terms of combat characteristics can be considered the Jagdpanther tank destroyer, but there were three times less of them built during the war years.
The most prominent role was played by the SU-100 during the Balaton operation, they were used very effectively on March 6-16, 1945 when repelling counterattacks by the 6th SS Panzer Army. The self-propelled guns of the 207th, 208th and 209th self-propelled artillery brigades, as well as several separate SAPs, took part in the battles. During the operation, the SU-100 proved to be a highly effective means in the fight against German heavy armored vehicles.
It was the SU-100 that became the real "St. John's Wort", although for some reason in the memoir, "near-documentary" and fiction literature, these laurels were given to the heavy SU-152 and ISU-152, which much less often entered into fire duels with German tanks. Taking into account post-war production, the number of SU-100 built exceeded 3000 units. In the 50-70s, these self-propelled guns were repeatedly modernized, and in our country they were in service until the early 90s.
