The autopsy showed: M60A1 in Kubinka

In Focus
The main testing ground for armored vehicles in Soviet times and now is the military unit in Kubinka near Moscow. During times of total secrecy, it was known under the number 68054. Of course, foreign samples of military equipment were of greatest interest to local engineers. In one of previous articles we were talking about the British tank Chieftain Mk5R, which came to the Soviet Union during the Iran-Iraq War. But it was quite an exotic car for its time, and in many respects it did not reach the world’s best representatives. Today we will talk about the M-60A1 tank, which arrived in the USSR from the Yom Kippur War in the fall of 1973. The American was of interest to domestic engineers primarily because it was the most popular foreign tank for its time. In the event of the outbreak of world war, Soviet tankers would have encountered precisely this vehicle, and only then the Leopard or Chieftain. Therefore, the weaknesses and strengths of the tank had to be probed and documented. And, as they wrote then, materials
M-60A1 was studied in Kubinka from November 1973 to June 1975. The vehicle was dissected in great detail, involving specialists from “mailbox A-7701” - that was the name of the head armored tank VNIITransmash of the 12th Main Directorate of the Defense Industry. A detailed report was published in two issues of the specialized and secret scientific and technical collection “Issues of Defense Technology” in 1976. By the way, it was declassified only eight years ago.
A 1972 tank fell into the hands of Soviet engineers, differing from later vehicles in the absence of a stabilizer, a heat-protective gun casing and less durable tracks. As is usually the case with vehicles coming from war, the M-60A1 arrived "partially restored and not fully completed" Currently, this tank can be admired at the exhibition of the Patriot Park in Kubinka. It makes no sense to dwell in detail on the design of the American car - there is enough information on this matter on the Internet. Much more interesting is the assessment given by domestic researchers of the tank in their detailed reports. No less than fifty engineers took part in the study of the M-60A1, and they worked the foreigner very thoroughly. Suffice it to say that a separate work was devoted to the maintainability of the tank, which took into account the time to replace the power unit and even the tightening torques of the bolted connections of the chassis.
In the field of layout solutions for the M-60A1, the tank's leakage attracted special attention from engineers. The report states that
Among the advantages, units and blocks also stood out, most of which were easily removable, which made it possible to quickly and easily dismantle and replace them. The equipment was attached through damping devices, which increased the survivability of the tank during shell fire. Especially when the armor was not hit through.
American gun
The strength of NATO equipment has always been its guns, and the M-60A1 tank was no exception. The 105-mm M-68 gun was distinguished by high bending rigidity - 470 kgf/cm. But, despite this, thermal protective devices have been introduced for gun barrels since 1975, reducing the influence of external factors (sun, wind, precipitation) on the thermal bending of the barrel. In addition, the design features of the gun made it insensitive to the effects of its own shot and, as a result, ensured high accuracy and accuracy of fire. In addition to the cannon of the M-60A1 tank, by the mid-70s the Soviet Union had a sample of the 105-mm French L-51 cannon, which was installed on the Super Sherman tank. The American cannon was compared with this weapon, and at the same time some ammunition was used for field testing. Firing in Kubinka was carried out with several types of shells:
- sub-caliber projectiles L-28A1 made in England and M-392A2 made in the USA with carbide tungsten carbide cores;
- English-made L-52A2 and L-52A3B1 sub-caliber projectiles with heavy alloy cores;
- cumulative American M-456A1 with floating driving belts and caliber empennage, as well as the French-made Obus G model F1 product with a rotating cumulative unit;
- British armor-piercing high-explosive shells L-35A2;
- Israeli armor-piercing high-explosive and high-explosive fragmentation L-35.
The armor-piercing effect of sub-caliber and cumulative ammunition was assessed under the given conditions - by firing at a range of 100 m at cards of monolithic steel armor of medium hardness. The required reduction in projectile speed was achieved by changing the mass of the powder charge.

Below is the text of the report:
- when firing from the M-68 cannon with American M-456A1 feathered projectiles, the maximum penetration depth of the cumulative jet is 434 mm, the minimum is 355 mm;
- when firing from the L-51 cannon with French Obus G model F1 shells with a rotating cumulative unit, the maximum penetration depth of the jet is 423 mm, the minimum is 350 mm.
The armor-piercing effect of armor-piercing high-explosive projectiles was assessed by the presence of rear spalling on cards of monolithic steel armor of medium hardness when fired both from an estimated range of 100 m and from real distances of 600 and 1000 m.
Research has shown that L-35A2 armor-piercing high-explosive shells for the English 105-mm L-7A1 cannon, like shells for the French L-51 cannon, spalled on an armor plate 120 mm thick at an angle of 60 degrees and on a plate 80 mm thick at an angle of 70 degrees. angle 75 degrees. At an impact angle of XNUMX degrees, the projectile ricocheted.”
Tests of 105-mm armor-piercing high-explosive and cumulative shells showed that the products are weak in the fragmentation field. Most of the fragments are large (from 1x1 to 5x5 cm), and the number of lethal fragments that hit the target was 15-25 for armor-piercing high-explosive shells, and 20-30 for cumulative shells. For example, the L-35A2 armor-piercing high-explosive projectile left a crater up to half a meter deep and up to 1,8 meters in diameter. The performance of high-explosive fragmentation shells could not be fully assessed due to their small number. But they were clearly inferior in high-explosive action to other types of tested projectiles.
Based on the results of the research and firing, the engineers spoke very flatteringly about the characteristics of the M-60A1 tank’s gun, especially its high accuracy. And the use of new materials (plastics and alloys) makes it possible to obtain a fairly high level of action of armor-piercing projectiles in the weights and dimensions used. We were talking, in particular, about the leading obturating belt of a sub-caliber projectile made of plastic. This improved the conditions for the passage of the projectile along the barrel and reduced mechanical wear.
Armor and stuff
While the M-60A1 was more or less good with its main caliber, the Americans let us down with its armor. Firstly, the tank was not even equipped with anti-cumulative shields. Although already in those days, NATO vehicles were actively adopting such equipment - in particular, the German Leopard-1A4 and the British Chieftain. Secondly, the developed rear part increases the internal volume of the tower and gives it an oblong shape. According to domestic engineers, this forms a large “zaman” in the stern, which weakens protection against high-explosive fragmentation and armor-piercing high-explosive shells. Further in the text:
Traditionally, the Americans got it for the large frontal projection area of the M-60A1 - such a target is easier to hit than the T-64. The trophy differed unfavorably in its massiveness even from other foreign tanks. But at the same time, the huge reserved volume of the tank (18 cubic meters) freely accommodated four crew members and created comfortable working conditions for them.

To sum up, we can say that the Americans’ car turned out to be quite good, but it clearly did not live up to Soviet-style tanks. Among the variety of technical solutions of the M-60A1, only seven interesting solutions for their time attracted attention:
- a gun with low curvature and varying thickness of the barrel, installed in a massive cradle mask;
- symmetrical recoil devices;
- a system for duplicating the gunner's firing by the commander;
- a method for determining range using a rangefinder sight;
- block design of the engine-transmission unit using quick-release valve connections of oil and fuel lines;
- additional transmission pump for towing mode.
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