M-46 52P482 130-mm Towed Gun - In-accuracy
The accuracy of the M-46 130mm field gun, like any artillery piece, is influenced by several factors, including the quality of the gun, the ammunition used, crew training, and environmental conditions. The condition of the barrel and other components can significantly affect accuracy. A well-maintained gun with a good barrel will be more accurate. Consistent and high-quality ammunition contributes to better accuracy. Variations in the ammunition, such as differences in propellant charges or projectile weight, can reduce accuracy.
The skill and experience of the gun crew in aiming and firing the gun are crucial for accuracy. Proper use of fire control equipment and techniques can greatly enhance accuracy. The use of modern fire control systems, including targeting computers and advanced sighting equipment, can improve accuracy. However, older models like the M-46 may rely more on manual aiming and less advanced systems. Weather, wind, temperature, and atmospheric pressure can all impact the trajectory of the shell and, consequently, the accuracy.
Typical Circular Error Probable (CEP) for the M-46 130mm field gun is generally within the range of 0.5% to 1% of the range to the target. For example, at a range of 20 km, the CEP could be around 100 to 200 meters. CEP is a measure used to indicate the radius within which 50% of the projectiles are expected to fall. The consistency of fire can vary, but with proper conditions and skilled operation, the M-46 can achieve reasonable accuracy for a field gun of its era.
Forward observers can provide real-time adjustments to fire, improving accuracy on targets. Modern range-finding equipment and meteorological data can help adjust fire more accurately. Detailed firing tables and calculations based on range, elevation, and other factors are used to improve accuracy. While the M-46 may not match the precision of modern artillery with advanced fire control systems, it remains a capable and effective weapon when used correctly and under favorable conditions.
Despite all its advantages, the M-46 cannon had (or still has) one significant drawback. When designing the projectile, the designers, for reasons known only to them, laid down inflated requirements for the accuracy of the battle when firing at a maximum distance of D = 27,300 m.
When conducting tests, it is very difficult to obtain a grouping that meets the requirements of the drawing. The accuracy of combat on the terrain is determined by the ratio of the probable dispersion of projectiles - Vd to the firing distance - X, for field systems the ratio Vd / X is generally within 1/200. For M-46 projectiles, the denominator of this fraction is slightly larger, and it was not always possible to reach this "little", despite any efforts and tricks of the testing ground.
No one could change the denominator of the fraction to a smaller value, even to 1/200, since the old OF shell was adopted into service in the first half of the 20th century, and when designing new shells for the M-46, designers traditionally took into account the previously established requirements for accuracy of fire.
The value of the dispersion of shells by range - Vd is taken as the basis for calculating the norms of shell consumption for hitting (suppressing) targets and an increase in Vd will entail an increase in the number of shells, and this is an increase in the "cost-effectiveness" indicator. "What is written with a pen cannot be cut out with an axe," says a Russian proverb, although the shell designers, shell manufacturers and firing range workers understood that the requirements for the accuracy of the battle were too high, but they could do nothing. The "healthy" conservatism of the military prevailed: "why change anything when it is so good!"
At the same time, no one took into account how much effort, money and nerves were spent on repeated tests, approval and signing of various decisions and decrees at all possible levels. When asked, “Why is it that the accuracy required by the drawing is so often not achieved?” the designers of the projectiles responded something like this: “The reason is probably the insufficient gyroscopic stability of the projectile at the descending point of the trajectory.”
If the "hundred and thirty" arrived at the testing ground, intensive preparation began. Shooting was conducted from a firing position located on the first kilometer of the battlefield, where there was only one position left, since in connection with the construction of new workshops and structures for the production of missile systems on the test site, the main firing positions were moved eight kilometers forward. It was necessary to shoot from the M-46 almost from the territory of the nearby summer cottages. The width of the test site's battlefield was from 2 to 4 kilometers. The combat projectile fired from the cannon flew at altitudes of up to 10 km over the territory of the plant, built up with workshops and structures where people were located, and the assembly of missile systems was carried out.
As a rule, the tests were planned to be carried out during the lunch break in order to protect the production personnel in the workshops, but due to weather conditions or for some other reasons, this was not always possible.
Theoretically, during shooting, all people had to take cover, but in practice, these requirements, to put it mildly, were not always met. Errors in aiming the gun during shooting in such conditions could lead to unpredictable consequences, so the tests from the M-46 were conducted by experiment leaders with extensive experience.
For safety reasons, the first sighting shot was made with a projectile in an inert load, and the V-429 combat fuse, set to “O” (fragmentation action), was used with a cap to prevent premature rupture of the combat projectile on its trajectory in the event of an accidental collision with birds or when the projectile flew through an area of ??intense precipitation in the form of hail or heavy rain.
Early in the morning, the M-46 was placed on its front and transported along the road, and then along a dirt road, using an ATT or a tank to the firing position. The gun was installed on a platform knocked together from sleepers, the coulters of the frame were rested against oak logs, then the gun was pulled back using a tractor, sleepers were placed under the wheels, which were firmly nailed to the platform with staples. The gun simply could not move anywhere. In winter, a stove was lit in the dugout next to the OP in advance, then extinguished. Ammunition was brought in a closed car with a red flag and brought into the dugout to ensure stable temperature of the shots. At the same time, careful preparation of the gun for test firing was carried out.
The following checks were performed: control napkin - barrel cleanliness, zero aiming line, pressure in the recuperator, amount of fluid in the recoil brake, the operation of the balancing mechanism was checked especially carefully at an elevation angle of the barrel of 45 degrees. Such a pressure value in the balancing mechanism was set, at which the force on the flywheel was constant, and the barrel moved up and down in the range of 45 plus - minus one degree smoothly without sharp jerks.
And here almost a sacred rite began. The shooting was conducted, with the exception of rare cases, by the head of the testing bureau Lev Valerianovich Znamensky. After loading the gun with another shot, setting the calculated lateral deviation of the projectile from the central directrice of the range and aiming the crosshair of the PG-1 panorama at a remote aiming point of 1000 meters, he placed the quadrant with an established angle of 7-50 (45 degrees), elevation on the control platform according to the risks on the breech. The RO and the gunner, who slowly rotated the flywheel of the lifting mechanism, held their breath, looking at the slowly creeping air bubble of the quadrant, accompanying its movement with the words: "Just a little, a hair, it went over!!! Again!"
The aiming of each shot was sometimes repeated several times. Lev Valerianovich somehow sensed the moment when to give the gunner the command "Good!", so that he would stop rotating the flywheel of the lifting mechanism, taking into account the inertia of the barrel movement. But all these tricks did not always give the desired results.
Every third batch of shells "failed", i.e. the accuracy did not meet the requirements of the drawing. The only salvation for the factories was that during the repeated testing two groups from a batch of shells were fired, the result was calculated as the arithmetic mean of the two retested groups of shells. The average value of the two groups, as a rule, was satisfactory.
The 130-mm high-explosive fragmentation shell for the M-46 cannon, marked with the mystical number of the “baker’s dozen” - 13, which, according to popular belief, brings all sorts of troubles into life. The projectile was good in every way: its range was over 27 km, its trajectory was over 10 km, its destructive power was at the proper level, it was naval, coastal, and anti-aircraft, and the Indians loved it, as did the Pakistanis, even Saddam Hussein favored it. That is why the enterprise received export bonuses from everywhere for the production of these shells.
There was one bad thing: it didn’t want to maintain the required accuracy across the terrain. And it must be said that other shells are like people: it is written in the polygon format Vd/X = 1/150 or 1/180, but it gives on average 1/400, in the worst case 1/250. And for a 13-cm caliber shell 1/220 is specified, on average it creeps up to 1/250, but, unfortunately, too, too often much lower, up to 1/90. Everything was there: both increased dispersion of the entire test group, and detachments of individual shells from the group.
Because of the "failures", almost all tests were conducted directly in my presence or that of our SKB employees. Terrible nerves. As soon as the field workers take measurements and transmit the coordinates of the projectile impact points, you immediately calculate the total spread, divide by 4 (you get an approximate value - Vd) and calculate the ratio to the distance (Vd / X). In a minute you know the obtained shooting result with an accuracy of plus or minus 10%.
The situation was tense; the USSR Minister of Defense, Marshal of the Soviet Union D.F. Ustinov, the USSR Minister of Mechanical Engineering V.V. Bakhirev, and the USSR Minister of General Mechanical Engineering S.A. Afanasyev were monitoring the development of shots for the 130-mm naval assault rifle AK-130, their delivery for testing, and their direct delivery to the ships. Entire institutes, factories, and military organizations were drawn into the search for the cause of premature product failures. The interdepartmental government commission included directors of the organization and deputy ministers. All issues that were even slightly related to cases of unauthorized operation were thoroughly studied. According to A.A. Kallistov, “a technical solution was found,” but, unfortunately, he did not report the details.
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