In 1957, work began in our country on the creation of several promising armored vehicles designed to combat enemy tanks. "Theme No. 9", set by the resolution of the Council of Ministers, provided for the creation of a self-propelled anti-tank gun with the code "Taran". The result of this project was the emergence of ACS "Object 120" or SU-152, work on which was stopped at the stage of factory testing.
Anti-tank "Battering ram"
The development of the product "120" was carried out in the SKB Uralmashzavod under the leadership of GS. Efimova. The gun was ordered by SKB-172, headed by M. Yu. Tsirulnikov. Other enterprises were also involved in the project. In 1958, they determined the final appearance of the future ACS, after which the development of a technical project began. In 1959-60. the assembly of experimental guns and self-propelled guns was carried out.
"Object 120" was made on the basis of the existing ACS SU-152P with the replacement of some of the key units. The chassis with an armored front-engine hull and a tracked chassis has been preserved. In the aft part of the hull there was a fighting compartment, made on the basis of a full-revolving turret. The vehicle's armor consisted of rolled and cast parts up to 30 mm thick, providing protection against 57 mm shells.
The power unit included a V-105-V diesel engine with a capacity of 480 hp. With the help of a mechanical two-stream transmission, power was supplied to the front drive wheels. The self-propelled guns retained a seven-roller undercarriage with a torsion bar suspension capable of withstanding the recoil impulse. A 27-ton armored vehicle could reach speeds of more than 60-62 km / h and overcome various obstacles.
The turret housed an M69 smoothbore gun of 152, 4 mm caliber with a 9045 mm barrel (59 klb) and a muzzle brake, capable of using several types of separate-case loading shots. Due to the pressure in the channel up to 392 MPa, the acceleration of the sub-caliber armor-piercing projectile up to 1710 m / s was ensured. The shots were transported in a drum rack, which accelerated the loading process. Ammunition included 22 shells with casings. High-explosive fragmentation, sub-caliber and cumulative projectiles could be used.
Additional armament of the "Taran" included the KPV anti-aircraft machine gun; the machine gun paired with the cannon was absent. In case of an emergency, the crew of four had a pair of machine guns and a supply of hand grenades.
At the beginning of 1960 Uralmashzavod completed the construction of an experimental "Object 120" and performed part of the factory tests. Before their completion, after working on the tracks and at the shooting range, the project was closed. The customer considered that the self-propelled anti-tank gun was not of interest to the army, in contrast to promising missile systems for a similar purpose.
Advantages and disadvantages
In accordance with the terms of reference for the ROC "Taran", the self-propelled gun was supposed to show a direct shot range of 3000 m. From this distance, it was required to penetrate at least 300 mm of homogeneous armor at a meeting angle of 30 °. On the whole, these requirements were met. When fired from 3 km, the M69 cannon with a sub-caliber projectile (weight 11, 66 kg) could penetrate a 315-mm vertical armor plate. At a tilt of 30 ° - a plate with a thickness of 280 mm. High armor penetration was maintained at increased ranges.
Thus, the "Object 120" was capable of striking in a frontal projection all existing medium and heavy tanks of a potential enemy at ranges of kilometers, ie. from outside the range of effective response fire. The developed cumulative ammunition made it possible to obtain sufficient characteristics, and the 43.5-kg high-explosive fragmentation expanded the combat capabilities of the self-propelled gun.
High firepower was also provided by successful reloading means. After the shot, the gun returned to the loading angle, and the drum stack simplified the loader's work. Due to this, the crew could make up to 2 shots in 20 seconds. In this respect, the SU-152, at least, was not inferior to other vehicles with artillery weapons, incl. smaller calibers.
The disadvantage of the "Object 120" could be considered a relatively low level of protection. The most powerful sections of the hull and turret had armor only 30 mm thick, which protected only from small and medium caliber shells. The hit of ammunition from 76 mm and above threatened the most serious consequences. However, this feature of the ACS was not considered a disadvantage due to the low probability of being hit by enemy fire from ranges of 2.5-3 km.
Also, the overall parameters turned out to be not entirely successful, although forced. Despite the aft location of the fighting compartment, the barrel protruded several meters in front of the hull. This made it difficult to drive on difficult terrain or could even lead to various unpleasant incidents, incl. with a temporary loss of combat capability.
In general, the "Object 120" was a fairly successful anti-tank ACS for its time with high performance that met the requirements of the time. However, some features of this ACS could complicate operation; others promised rapid obsolescence, as the tanks of a potential enemy developed.
"Battering ram" against "Dragon"
The same resolution of the Council of Ministers in 1957 set “theme number 2” - the development of a tracked armored vehicle with specialized anti-tank missile weapons. The total of this project was the self-propelled ATGM "Object 150" / "Dragon" / IT-1, created by plant number 183 in cooperation with OKB-16 and other enterprises.
Object 150 was a substantially revised T-62 tank with standard armor and a power plant, but with a complete replacement of the fighting compartment equipment. Inside the car there were stowage and a feed mechanism for 15 guided missiles, as well as a retractable launcher. There were also optical and computing facilities for target search and fire control.
The Dragon's weapon was a 3M7 rocket with a length of 1240 mm, a diameter of 180 mm and a mass of 54 kg. The rocket had a solid propellant engine and developed a speed of 220 m / s. The guidance system is a semi-automatic radio command with the calculation of data by the onboard equipment of an armored vehicle. It provided firing at a range of 300-3000 m. The missile's cumulative warhead penetrated 250 mm of armor at an angle of 60 °.
After completing part of the work on two projects, the customer had to compare fundamentally different combat vehicles of the same purpose - and choose a more successful and promising one. As it turned out, there was no clear leader in such a comparison - both samples had advantages over each other.
In terms of mobility, both anti-tank systems were equal. In terms of protection, the Object 150 was the leader on a tank chassis with appropriate armor and a smaller frontal projection. The use of a chassis with a mass of ready-made units simplified the future operation of the "Dragon" in the army.
There was no clear leader in fighting qualities. In the entire range of operating ranges, the IT-1 could show, at least, not the worst armor penetration, or even surpass the "Taran" - due to the stable performance of the shaped charge. An important advantage was the availability of missile controls for more accurate shooting. Finally, the armament did not protrude beyond the hull and did not spoil the cross-country ability.
On the other hand, the SU-152 had no restrictions on the minimum firing range, could use shells for various purposes, carried a larger ammunition load and showed a better rate of fire. In addition, artillery shells were much cheaper than guided missiles. As for the lower armor penetration at long distances, then it was enough to defeat typical targets.
Difficult comparison
An analysis of the possibilities and prospects of the two facilities was carried out in the spring of 1960, and on May 30, its results were confirmed by a new resolution of the Council of Ministers. This document demanded to stop work on the "120" project - despite the fact that the self-propelled gun barely had time to enter the factory tests. The finished sample was later transferred to storage in Kubinka, where it remains to this day.
The IT-1 "missile tank" was recommended for further development with subsequent introduction into service. Work on it took several more years, and only in the mid-sixties did it go into a small series and ended up in the army. Fewer than 200 of these armored vehicles were built, and their operation lasted only three years. Then the idea of a tank with missile weapons was abandoned in favor of other concepts.
Reasons for refusal
Most often, the refusal from "Object 120" in favor of "Object 150" is explained by the specific views of the country's leadership, which paid increased attention to missile systems, incl. to the detriment of other areas. This explanation is logical and plausible, but, apparently, other factors also affected the fate of the anti-tank SPG.
One of the main factors that influenced the fate of the SU-152 may be its own technical features. It is easy to see that the highest combat characteristics of the "Taran" were provided, first of all, by the increase in the caliber and length of the barrel, which led to noticeable limitations and problems. In fact, the result is a "self-propelled gun of extreme parameters", capable of producing high performance, but having minimal potential for modernization.
The IT-1 was also not an ideal machine, but at that time it looked more successful and had better prospects. In addition, the concept of an ATGM on a self-propelled armored platform has fully justified itself and has been developed. Similar samples, although not on a tank base, are still being developed and put into service.
Third contender
In the sixties, after the abandonment of the "Object 120" / "Ram", the development of a new generation of smooth-bore tank guns of 125 mm caliber and ammunition for them began. Its result was the D-81 or 2A26 product and a whole line of shells for various purposes. The resulting complex of weapons in terms of their performance was at least as good as the "Taran" and "Dragon". Moreover, it could be widely used on new models of tanks. Later, on the basis of 2A26, they created the famous 2A46.
The emergence of new tank armament made it useless to further build up the caliber of self-propelled guns of the project "120" type. At the same time, tank guns did not interfere with the further development of anti-tank missiles, and then they themselves became launchers for such weapons. Large calibers remained in the hands of howitzer artillery, including self-propelled ones. However, they still returned to the idea of a 152-mm anti-tank gun, but this time in the context of tank armament.
