A special issue of the magazine "Arms Export" published an article by Alexey Degtyarev dedicated to the Soviet 122-mm howitzer D-30. The bmpd blog offers readers the full text. Illustrations for the article are available on the website of the Kalashnikov magazine.
122-mm guabits D-30A of the Russian Airborne Forces (c) Kalashnikov magazine website
By the first half of the 1950s, it became obvious that the Soviet Army was armed with a 122-mm divisional howitzer of the 1938 model (M-30), which was a reliable and mobile gun of classical design (carriage with two sliding frames, wheel travel mounted on the lower machine), had a number of shortcomings identified in during the Great Patriotic War.
Sighting devices that did not guarantee a direct hit at medium and long distances sharply reduced the effectiveness of the M-30 as an anti-tank gun. If in the first months of the war there was a high-explosive shell close enough to the target to hit the enemy's light tanks, then with increased protection and an increase in the mass of armored vehicles, even the presence of cumulative ammunition did not guarantee the destruction of the object.
In addition to the two calculation numbers required for rapid targeting (horizontal and vertical guidance flywheels were located on opposite sides of the breech), to ensure an acceptable rate of fire, a third calculation number was required - the lock number, which was responsible for the timely opening of the piston bolt.
In the event of an enemy appearing outside the firing sector (the horizontal aiming angle of the M-30 was 49°), at least four calculation numbers and precious time were required to turn the 2.5-ton gun.
There was a need to realize for the divisional howitzer the possibility of circular firing, which had previously been characteristic mainly of anti-aircraft guns.
By Resolution of the Council of Ministers of the USSR No. 598-265 of April 2, 1954, OKB-9 was tasked with developing a 122-mm divisional howitzer to replace the M-30.
At the initial stages of development, the option of upgrading the M-30 howitzer was considered, but the requirement for circular firing dictated either the installation of a pallet with a jack on the lower machine, or the use of completely new design solutions. The choice was made in favor of the second option, since it promised a much higher speed of horizontal aiming.
In December 1954, the Main Artillery Directorate received a draft design of the D-30 howitzer, and on January 29, 1955, it was already approved.
After almost five years of factory and military tests, by Decree of the Council of Ministers of the USSR No. 489-198 of May 12, 1960, the 122-mm howitzer D-30 was adopted and received the GAU index 2A18.
The D-30 three-column carriage, unique for artillery systems of this class, not only provided a 360° horizontal aiming angle, but also provided completely new opportunities for transporting guns and significantly increased mobility.
In the marching position, two frames are reduced to a third (stationary) under the barrel, which makes the gun very compact, and the torsion bar suspension provides an acceptable towing speed of 80 km / h (also, thanks to torsion bars, the lifting of the wheels by calculation numbers is facilitated when transferring the D-30 from the marching position to the combat position).
Speaking of compactness in the marching position, we can mention the concept of a Skoda circular firing gun presented in 1943 on a four-column carriage with a lowered wheel travel. On the march, the frames were reduced in two opposite directions: the first pair was fastened to the trunk, and the second was coupled to the tractor. It is obvious that the comparative dimensions of such a gun in the marching position are at least one and a half times larger than that of the towed D-30.
When transferring the D-30 howitzer from the marching position to the combat gun, it rises on a jack, the movable frames are separated by 120 ° relative to the stationary one and fixed with stoppers, and the wheels rise to the upper position, after which the jack is lowered.
In the combat position, the wheels are fixed at such a height that when the gun is rotated, they freely pass over the frames - this is the reason for the design decision to fix the wheels on the upper machine.
The anti-recoil devices of the D-30 are located in the clip on the breech, above the barrel, which had a positive effect on the stability of the gun, and also allowed to reduce the line of fire and, consequently, reduce the dimensions of the gun in height in combat position and increase its survival on the battlefield.
When it comes to the three-column carriage and the possibility of circular firing at the D-30, questions may arise about the originality of this solution.
Indeed, 10 years before the task was set to develop a 122-mm divisional howitzer to replace the M-30 (with a mandatory requirement - the presence of circular firing), there were already examples of such systems in Germany, France and Czechoslovakia. At the same time, it is worth noting that the availability of information about them for Soviet designers was extremely low, and almost all of these designs remained only projects and concepts.
In 1943, the above-mentioned project of a Skoda gun on a four-column carriage was approved by the Armament Directorate of the Third Reich Land Forces, after which it was transferred to the Krupp concern. The concern's specialists revised the Czechoslovak design and placed the rotating part of the 105 mm caliber (from the leFH 18 light field howitzer, it was also installed on the Skoda concept) on the carriage from the Pak 43 heavy anti-tank gun with circular firing.
In view of the obvious inconsistency of this decision, the German designers offered their own version of the carriage in the image and likeness of Skoda.
But the hybrid leFH 18 and Pak 43 (leFH 43) was destined to remain in the status of the concept. Until the end of the war, only a few copies were produced in Nazi Germany, which is where the history of the sample ended.
Of course, we can say that as a result of the war, many German developments fell into the hands of Soviet designers and were thoroughly studied, but even with a superficial comparison of the leFH 18 and D-30, it becomes clear that these are completely different systems.
It is worth paying attention to the fact that the design solution for installing the rotating part on a trolley with four wheels hanging forward, used in the German Pak 43 cannon, was also not unique. In 1940, three years before the construction of the first prototype Pak 43, the USSR tested a 100-mm "stratospheric" gun L-6 of a similar layout, which, of course, should be considered primary in relation to the German gun.
The French project of the 47 mm SA Mle 1939 TAz anti-tank gun with circular firing is also of interest. At the first glance at the archival photos of this system, obvious similarities with the D-30 are striking: a three-column carriage and high-set wheels for their free movement over the frames when turning the rotating part. However, the gun does not have a jack, and the frames themselves are of a completely different design - they, like the German gun, are separated in two directions in the marching position.
In addition, the device of the French small-caliber anti-tank gun does not imply the possibility of mortar firing (the range of vertical aiming angles of SA Mle 1939 is from -13° to +14°), while the carriage of the 122-mm D-30 howitzer allows firing at vertical aiming angles from -7° to +70°.
As in the case of the 105-mm German gun, in 1940 only a few samples of the SA Mle 1939 were produced, the trace of which is lost in the future.
Some captured samples of systems with circular firing could theoretically be at the disposal of Soviet specialists. However, due to the cardinal design differences of the D-30 from the systems mentioned above, it is not necessary to talk about its secondary nature in relation to foreign models. Moreover, information about the Soviet 45-mm anti-tank gun with circular firing I13-60 with a three-column carriage modeled after the British 2-pounder anti-tank gun QF 2-pounder has been preserved in the domestic history of weapons.
From the point of view of the layout, the Soviet experimental cannon was distinguished from the English product primarily by hanging the wheels in the combat position instead of laying them on the ground between the frames. It was this architecture that formed the basis for the design of the 122-mm D-30 howitzer, which became one of the most successful artillery pieces of the twentieth century.
Currently, the D-30 howitzer is in service in dozens of countries around the world. In addition to domestic modifications, for more than half a century of the history of the gun, different countries have presented their own versions of the system, including self-propelled artillery installations.
With regard to the conflicts of the XXI century, it should be noted separately the use of D-30 howitzers on the line of confrontation between the Armed forces of Ukraine (AFU) and military formations of the Donetsk and Lugansk People's Republics.
As of 2014, there were about 100 D-30/A units in the Armed Forces of Ukraine, most of which belonged to guns produced before the modernization of the howitzer in 1978.
Until the spring of 2022, they were actively used by the Armed Forces of Ukraine in the Donbass both as part of batteries and divisions, and as single guns attached to strengthen in certain areas of combat operations.
After the start of Russia's special military operation on the territory of Ukraine on February 24, 2022, Ukrainian D-30s were catastrophically quickly and almost completely spent, being unable to withstand the firepower of the Russian side in general and long-range artillery systems of larger calibers in particular.
The Russian Armed Forces in the course of their military operations in Ukraine use 122-mm D-30 howitzers exclusively in the combat formations of airborne troops. This is due to the fact that in 2013 it was decided to completely replace the 122-mm towed artillery systems with self-propelled ones.
En masse, the D-30 remained exclusively in service with the Airborne Forces, since its small weight and small dimensions simplify the air transportation of guns and provide the possibility of parachuting.
Due to the high level of training of D-30 paratroopers in Ukraine, they are especially effectively used in suppressing enemy mortar positions identified by modern means of reconnaissance.
Summing up, it is safe to assume that, given the ease of operation and high reliability, the D-30 - a unique Soviet howitzer - will remain the most effective towed artillery system in its class for many decades to come.
