Before the war in the USSR, numerous attempts were made to create various self-propelled artillery installations (ACS). Dozens of projects were considered, for many of them prototypes were built. But it never came to mass adoption. The exceptions were: 76-mm anti-aircraft gun 29K on the chassis of the YAG-10 truck (60 pcs.), ACS SU-12 - 76, 2-mm regimental cannon model 1927 on the chassis of the Morland or GAZ-AAA truck (99 pcs.)), ACS SU-5-2 - 122-mm howitzer installation on the T-26 chassis (30 pcs.).
SU-12 (based on the Morland truck)
Of greatest interest in the anti-tank relation was the SU-6 self-propelled guns on the chassis of the T-26 tank, which was not accepted for service, armed with a 76-mm 3-K anti-aircraft gun. The tests of the installation took place in 1936. The military was not satisfied that the calculation of the SU-6 in the stowed position did not fit completely on the ACS and the installers of the remote tubes had to go in an escort car. This led to the fact that the SU-6 was declared unsuitable for escorting motorized columns as a self-propelled anti-aircraft gun.
ACS SU-6
Although the possibility of using it to combat tanks was not considered, self-propelled guns armed with such weapons could be an excellent anti-tank weapon. Fired from the 3-K gun, the BR-361 armor-piercing projectile, at a distance of 1000 meters, penetrated 82-mm armor along the normal. Tanks with such armor were used in large quantities by the Germans only since 1943.
In fairness, it should be said that in Germany at the time of the invasion of the USSR, there were also no serial anti-tank self-propelled guns (PT self-propelled guns). The first versions of the StuG III "Artshturm" self-propelled guns were armed with short-barreled 75-mm guns and did not have significant anti-tank capabilities.
German SPG StuG III Ausf. G
However, the presence of a very successful machine in production made it possible in a short time, by building up frontal armor and installing a 75-mm gun with a barrel length of 43 caliber, to turn it into an anti-tank one.
In the course of the very first battles of the Great Patriotic War, the question of the need to develop an anti-tank self-propelled artillery installation capable of quickly changing positions and fighting German tank units, which significantly surpassed the Red Army units in terms of mobility, arose sharply.
As a matter of urgency, a 57-mm anti-tank gun Model 1941, which had excellent armor penetration, was installed on the chassis of the Komsomolets light tractor. At that time, this gun confidently hit any German tank at real combat distances.
PT ACS ZIS-30 was a light anti-tank installation of an open type.
The combat crew of the installation consisted of five people. The upper machine tool was mounted in the middle of the machine body. The vertical guidance angles ranged from -5 to + 25 °, horizontally in the 30 ° sector. The shooting was carried out only from the spot. The stability of the self-propelled unit when firing was ensured with the help of folding openers located in the rear of the vehicle body. For self-defense of the self-propelled unit, a standard 7, 62-mm DT machine gun was used, which was installed in a ball joint on the right in the frontal sheet of the cockpit. To protect the crew from bullets and shrapnel, an armored shield cover of the gun was used, which had a hinged upper part. In the left half of the observation shield, there was a special window, which was covered by a movable shield.
PT ACS ZIS-30
Production of the ZIS-30 lasted from September 21 to October 15, 1941. During this period, the plant produced 101 vehicles with a ZIS-2 cannon (including a prototype vehicle) and one installation with a 45 mm cannon. Further production of installations was stopped due to the lack of discontinued "Komsomoltsy" and the cessation of production of 57-mm guns.
The ZIS-30 self-propelled guns began to enter the troops at the end of September 1941. They were used to supply anti-tank batteries of 20 tank brigades of the Western and Southwestern Fronts.
In the course of intensive use, the self-propelled gun revealed a number of disadvantages, such as poor stability, congestion of the undercarriage, a small cruising range, and a small ammunition load.
By the summer of 1942, there were practically no ZIS-30 tank destroyers left in the army. Some of the vehicles were lost in battles, and some were out of order for technical reasons.
Since January 1943, serial production of the created by N. A. Astrov based on the T-70 light tank, self-propelled 76-mm SU-76 installations (later Su-76M). Although this light self-propelled gun was very often used to combat enemy tanks, it cannot be considered anti-tank. The armor protection of the SU-76 (forehead: 26-35 mm, side and stern: 10-16 mm) protected the crew (4 people) from small arms fire and heavy fragments.
ACS SU-76M
With proper use, and this did not come immediately (an ACS is not a tank), the SU-76M performed well both in defense - when repelling infantry attacks and as mobile, well-protected anti-tank reserves, and in an offensive - when suppressing machine-gun nests, destroying pillboxes and bunkers, as well as in the fight against counter-attacking tanks. The ZIS-3 divisional gun was installed on the armored vehicle. Its sub-caliber projectile from a distance of 500 meters pierced armor up to 91 mm, that is, any place in the hull of German medium tanks and the side of the "panther" and "tiger".
In terms of armament characteristics, the SU-76M was very close to the SU-76I ACS, created on the basis of captured German tanks Pz Kpfw III and ACS StuG III. Initially, it was planned to install in the fighting compartment of ACS 76, a 2-mm ZIS-3Sh cannon (Sh - assault), it was this modification of the gun that was installed on the serial ACS SU-76 and SU-76M on a machine fastened to the floor, but such an installation did not provide a reliable protection of the gun embrasure from bullets and shrapnel, since cracks were invariably formed in the shield when lifting and turning the gun. This problem was solved by installing a special self-propelled 76, 2-mm gun S-1 instead of the 76-mm divisional gun. This gun was designed on the basis of the F-34 tank gun, which was equipped with the T-34 tanks.
ACS SU-76I
With the same firepower as the SU-76M, the SU-76I was much more suitable for use as an anti-tank because of its better protection. The front of the hull had anti-cannon armor with a thickness of 50 mm.
Production of the SU-76I was finally stopped at the end of November 1943 in favor of the SU-76M, which had already gotten rid of "childhood illnesses" by that time. The decision to discontinue production of the SU-76I was associated with a reduction in the number of Pz Kpfw III tanks used on the Eastern Front. In this regard, the number of captured tanks of this type decreased. A total of 201 SU-76I self-propelled guns were produced (including 1 experimental and 20 commander ones), which took part in the battles of 1943-44, but due to the small number and difficulties with spare parts, they quickly disappeared from the Red Army.
The first specialized domestic tank destroyer capable of operating in battle formations along with tanks was the SU-85. This vehicle became especially popular after the appearance of the German PzKpfw VI "Tiger" tank on the battlefield. The Tiger's armor was so thick that the F-34 and ZIS-5 guns installed on the T-34 and KV-1 could penetrate it with great difficulty and only at suicidal close distances.
Special firing at a captured German tank showed that the M-30 howitzer installed on the SU-122 has an insufficient rate of fire and low flatness. In general, for firing at fast-moving targets, it turned out to be little adapted, although it had good armor penetration after the introduction of cumulative ammunition.
By order of the State Defense Committee dated May 5, 1943, the design bureau under the leadership of F. F. Petrov launched work on the installation of an 85-mm anti-aircraft gun on the SU-122 chassis.
Tank destroyer SU-85 with D-5S cannon
The D-5S cannon had a barrel length of 48.8 caliber, the firing range of direct fire reached 3.8 km, the maximum possible - 13.6 km. The range of elevation angles was from −5 ° to + 25 °, the horizontal firing sector was limited to ± 10 ° from the longitudinal axis of the vehicle. The ammunition load of the gun was 48 rounds of unitary loading.
According to Soviet data, the 85-mm armor-piercing projectile BR-365 normally pierced an armor plate 111 mm thick at a distance of 500 m, and 102 mm thick at twice the distance under the same conditions. The sub-caliber projectile BR-365P at a distance of 500 m along the normal pierced the armor plate 140 mm thick.
The control compartment, engine and transmission, remained the same as that of the T-34 tank, which made it possible to recruit crews for new vehicles practically without retraining. For the commander, an armored cap with prismatic and periscopic devices was welded in the roof of the wheelhouse. On SPGs of later releases, the armor cap was replaced with a commander's cupola, like that of the T-34 tank.
The general layout of the vehicle was similar to the layout of the SU-122, the only difference was in the armament. The security of the SU-85 was similar to that of the T-34.
Cars of this brand were produced at Uralmash from August 1943 to July 1944; a total of 2337 self-propelled guns were built. After the development of the more powerful SU-100 self-propelled gun due to the delay in the release of 100-mm armor-piercing shells and the termination of the production of armored hulls for the SU-85 from September to December 1944, the transitional version of the SU-85M was produced. In fact, it was a SU-100 with an 85 mm D-5S cannon. The modernized SU-85M differed from the original version of the SU-85 in more powerful frontal armor and increased ammunition. A total of 315 of these machines were built.
Thanks to the use of the SU-122 hull, it was possible to very quickly establish the mass production of the SU-85 tank destroyer. Acting in battle formations of tanks, they effectively supported our troops with fire, hitting German armored vehicles from a distance of 800-1000 m. The crews of these self-propelled guns were especially distinguished when crossing the Dnieper, in the Kiev operation and during the autumn-winter battles in the Right-Bank Ukraine. Except for the few KV-85 and IS-1, before the appearance of the T-34-85 tanks, only the SU-85 could effectively fight enemy medium tanks at distances of more than a kilometer. And at shorter distances and to penetrate the frontal armor of heavy tanks. At the same time, already the first months of using the SU-85 showed that the power of its gun was insufficient to effectively combat enemy heavy tanks, such as the Panther and Tiger, which, having an advantage in firepower and protection, as well as effective aiming systems, imposed a battle from long distances.
Built in the middle of 1943, the SU-152 and the later ISU-122 and ISU-152 hit any German tank in the event of a hit. But for the fight against tanks, due to their high cost, bulkiness and low rate of fire, they were not very suitable.
The main purpose of these vehicles was the destruction of fortifications and engineering structures and the function of fire support for the advancing units.
In mid-1944, under the leadership of F. F. Cannon D-10S mod. 1944 (index "C" - self-propelled version), had a barrel length of 56 calibers. An armor-piercing projectile of the cannon from a distance of 2000 meters hit the armor with a thickness of 124 mm. A high-explosive fragmentation projectile weighing 16 kg made it possible to effectively hit manpower and destroy enemy fortifications.
Using this weapon and the base of the T-34-85 tank, the designers of Uralmash quickly developed the SU-100 tank destroyer - the best anti-tank self-propelled gun of the Second World War. Compared to the T-34, the frontal armor was increased to 75 mm.
The gun was installed in the frontal slab of the cabin in a cast frame on double pins, which allowed it to be guided in the vertical plane within the range from −3 to + 20 ° and in the horizontal plane ± 8 °. Guidance was carried out using a sector-type manual lifting mechanism and a screw-type rotary mechanism. The ammunition load of the gun consisted of 33 unitary rounds, placed in five stowages in the wheelhouse.
The SU-100 possessed firepower exceptional for its time and was capable of fighting all types of enemy tanks at all ranges of aimed fire.
Serial production of the SU-100 began at Uralmash in September 1944. Until May 1945, the plant managed to produce more than 2,000 of these machines. The SU-100 was produced at Uralmash at least until March 1946. Omsk Plant No. 174 produced 198 SU-100s in 1947, and 6 more at the beginning of 1948, producing a total of 204 vehicles. The production of the SU-100 in the post-war period was also established in Czechoslovakia, where in 1951-1956 another 1420 SPGs of this type were released under license.
In the postwar years, a significant part of the SU-100 was modernized. They were equipped with night observation devices and sights, new fire-fighting and radio equipment. The ammunition load was supplemented with a shot with a more effective UBR-41D armor-piercing projectile with protective and ballistic tips, and later with subcaliber and non-rotating cumulative projectiles. The standard ammunition of the ACS in the 1960s consisted of 16 high-explosive fragmentation, 10 armor-piercing and 7 cumulative shells.
Having one base with the T-34 tank, the SU-100 has spread widely around the world, officially in service in more than 20 countries, they have been actively used in numerous conflicts. In a number of countries, they are still in service.
In Russia, the SU-100 could be found "in storage" until the end of the 90s.
