Military Review

Conical Steam Guns

For centuries, fast-moving scrap has remained the best anti-tank ammunition. And the main issue over which gunsmiths are fighting is how to disperse it quickly

This is only in films about the Second World War Tanks after a shell hits, a movie, after all. In real life, most tanks die as foot soldiers, catching their bullet on full run. A caliber projectile makes a small hole in the thick body, killing the crew with fragments of the armor of the tank itself. True, unlike the infantryman, most of these tanks in a few days, or even hours, easily come back to life. True, with a different crew.

Conical Steam Guns
The modern reconstruction of a cannon with a tapered barrel clearly shows a characteristic detail: the shield is made up of two armor plates

Almost until the beginning of the Second World War, the speed of conventional field artillery shells with a reserve was enough to penetrate the armor of any tanks, and the reservation was mostly bulletproof. The classic armor-piercing projectile consisted of a large blunt steel (not to slide off the armor and not break off the tip of the projectile) piercer, often with aerodynamic copper cap-fairing and a small amount of explosives in the bottom part - there was not enough reserves of own armor in pre-war tanks for a good co-formation.

Everything changed. 18 December 1939, when, supporting the advance of the Soviet infantry, the experienced tank KV-1 attacked the Finnish positions. 43 artillery shells hit the tank, but none of them pierced the armor. However, for unknown reasons, this debut was not noticed by specialists.

Therefore, the appearance on the front of Soviet tanks with anti-missile armor — heavy KV and medium T-34 — was an unpleasant surprise for the Wehrmacht generals. In the very first days of the war, it became clear that all the Wehrmacht’s anti-tank guns and thousands of trophy guns — British, French, Polish, Czech — were useless in the fight against HF tanks.

It should be noted that the German generals responded fairly quickly. Corps artillery was thrown against KV - 10,5-cm guns and 15-cm heavy howitzers. But the most effective means of dealing with them were anti-aircraft guns of the 8,8 and 10,5 calibers. In a few months, fundamentally new armor-piercing shells, sub-caliber and cumulative (according to Soviet terminology, armored) were created.

German 20 / 28-mm anti-tank gun sPzB 41. Due to the conical barrel, which gave a greater initial velocity to the projectile, it penetrated the armor of the T-34 and KV tanks

Mass and speed

Let's leave cumulative ammunition aside - we told about them in the previous numbers of "PM". The armor penetration of classic, kinetic projectiles depends on three factors - the impact force, the material and the shape of the projectile. Increase the impact force can increase the mass of the projectile or its speed. Increasing the mass while maintaining the caliber is permissible within very small limits; the speed can be increased by increasing the mass of the propellant charge and increasing the length of the barrel. Literally, in the first months of the war, the walls of the barrels of anti-tank guns thickened, and the barrels themselves became longer.

A simple increase in caliber was also not a panacea. Powerful anti-tank guns of the beginning of the Second World War were done mainly as follows: they took the swinging parts of anti-aircraft guns and put them on heavy gun carriages. Thus, in the USSR, an 34-mm BS-100 anti-tank gun with a weight of 3 mt warhead was created on the basis of the rocking part of the ship's anti-aircraft gun B-3,65. (For comparison: the German 3,7-cm anti-tank gun weighed 480 kg). The BS-3 was even ashamed to call us an anti-tank gun and called the field gun, the Red Army had no field guns before that, this is a pre-revolutionary term.

The Germans based 8,8-cm anti-aircraft gun "41" created two types of anti-tank guns weighing 4,4 – 5 t. Based on the 12,8-cm anti-aircraft gun, several samples of anti-tank guns with quite transcendent weight 8,3 – 12,2 t were created. They needed powerful tractors, and the disguise was difficult due to the large size.

These guns were extremely expensive and were produced not by the thousands, but by the hundreds in Germany and in the USSR. Thus, by May 1, 1945 of the Red Army consisted of 403 units 100-mm guns BS-3: 58 - in corps artillery, 111 - in army artillery and 234 - in RVGK. And in the divisional artillery they were not at all.

The design of shells allowed them to shrink in the barrel

Forced guns

Much more interesting was another way of solving the problem - while maintaining the caliber and mass of the projectile to disperse it quickly. Many various options were invented, but anti-tank cannons with a conical bore channel turned out to be a real masterpiece of engineering thought. Their trunks consisted of several alternating conical and cylindrical sections, and the projectiles had a special design of the leading part, allowing for a decrease in its diameter as the projectile moved along the channel. Thus, the most complete use of the pressure of powder gases to the bottom of the projectile was ensured by reducing the area of ​​its cross section.

This ingenious solution was invented before the First World War - the German Karl Ruff received the first patent for a gun with a conical bore in 1903 year. Conducted experiments with a conical bore in Russia. In 1905, engineer M. Druganov and General N. Rogovtsev proposed a patent for a rifle with a conical bore. And in 1940, in the design office of the artillery plant No. 92 in Gorky, prototypes of a barrel with a conical channel were tested. During the experiments, we managed to get the initial velocity 965 m / s. However, V.G. Grabin could not cope with a number of technical difficulties associated with the deformation of the projectile during the passage of the bore, and to achieve the desired quality of channel processing. Therefore, even before the start of World War II, the Main Artillery Directorate ordered the discontinuation of experiments with barrels with a conical canal.

Dark Genius

The Germans continued their experiments, and already in the first half of 1940, a heavy anti-tank gun, s.Pz.B.41, was taken into service, the barrel of which had a 28 mm caliber at the beginning of the channel, and a 20 mm for the barrel. The gun system was called for bureaucratic reasons, but in fact it was a classic anti-tank gun with wheel chocks and with a wheel drive, and we will call it a gun. With an anti-gun, it was brought closer only by the absence of targeting mechanisms. The barrel manually directed the gunner. The gun could be pulled apart. The fire could be carried out from the wheels and from the bipod. For the airborne troops produced a lightweight version of the gun, which is lightened to 118 kg. This cannon had no shield, and light alloys were used in the construction of the mast. Established wheels replaced by small rollers without any suspension. The weight of the gun in the combat position was only 229 kg, and the rate of fire - up to 30 shots per minute.

The ammunition consisted of a subscaliber projectile with a tungsten core and fragmentation. Instead of copper bands used in classic shells, both shells had two centering annular ledges of soft iron, which were crushed when fired and crashed into the grooves of the barrel. During the passage of the entire path of the projectile through the channel, the diameter of the annular projections decreased from 28 to 20 mm.

The fragmentation projectile had a very weak damaging effect and was intended solely for self-defense calculation. But the initial speed of the armor-piercing projectile was 1430 m / s (against the 762 m / s of the classic 3,7-cm anti-tank guns), which puts s.Pz.B.41 on a par with the best modern guns. For comparison, the best in the world 120-mm German tank gun Rh120, standing on the tanks Leopard-2 and Abrams M1, accelerates sabot projectile to 1650 m / s.

By 1 June 1941, the troops had X. NUMX guns of s.Pz.B.183, in the same summer they received their baptism of fire on the Eastern Front. In September 41, the last cannon, s.Pz.B.1943, was commissioned. The cost of one gun was 41 Reichsmarks.

At short distances 2,8 / 2-cm guns easily hit any medium tanks, and with a successful hit, heavy tanks of the type KV and IP were also out of action.

Soviet 76 / 57-mm C-40 gun with a cylindrical-conical bore

Caliber more speeds below

In 1941, the 4,2-cm anti-tank gun mod. 41 (4,2 cm Pak 41) from Rheinmetall with a conical bore. Its initial diameter was 40,3 mm, the final diameter was 29 mm. In 1941, 27 4,2-cm guns arr. 41, and in 1942, 286. The initial speed of the armor-piercing projectile was 1265 m / s, while at the 500 distance m it punched 72-mm armor at an angle of 30 °, and normal - 87-mm armor. The weight of the gun was 560 kg.

The most powerful serial anti-tank gun with a conical channel was the 7,5 сm Pak 41. Its design was started by Krupp back in 1939 year. In April – May 1942, the Krupp company released a batch of 150 products, on which their production ceased. The initial speed of the armor-piercing projectile was 1260 m / s, at the 1 km distance he punched 145-mm armor at an angle of 30 ° and 177-mm normal, that is, the gun could fight all types of heavy tanks.

Short life

But if the conical barrels were not widely used, it means that these guns had serious flaws. Our specialists considered the main factor to be the low survivability of the conical barrel (on average, about 500 shots), that is, almost ten times less than that of the 3,7-cm anti-tank gun Pak 35 / 36. (The argument, by the way, is unconvincing - the probability of surviving for a light anti-tank gun that fired 100 rounds on tanks did not exceed 20%. And not one survived to 500 rounds.) The second complaint is the weakness of fragmentation shells. But the gun is anti-tank.

Nevertheless, the German guns made an impression on the Soviet military, and immediately after the war, work began on the Russian anti-tank guns with a conical bore in the TsARKB (KB Grabina) and OKB-172 ("sharashka", where the cons worked). On the basis of the 7,5 trophy cannon cm PAK 41 with a cylindro-tapered barrel at TsAKB, in 1946, work began on 76 / 57-mm C-40 regimental anti-tank cannon with a cylindro-tapered barrel. The C-40 barrel had a caliber in the breech 76,2 mm, and in the muzzle - 57 mm. The full barrel length was about 5,4 m. Camé was borrowed from the 85-mm anti-aircraft gun model 1939 of the year. A conical threaded part of 76,2 mm caliber 3264 mm long with 32 cuts of constant steepness in 22 caliber went behind the camera. A nozzle with a cylindrical-conical channel is screwed onto the muzzle of the pipe. The weight of the system was 1824 kg, the firing rate was up to 20 rds / min, and the initial speed of the 2,45-kilogram armor-piercing projectile was 1332 m / s. Normally, at a distance of 1 km, a shell pierced 230-mm armor, for such a caliber and weight of the gun it was a fantastic record!

A prototype of the C-40 gun passed factory and field tests in the 1947 year. The combat accuracy and armor penetration capability of the C-40 armor-piercing projectiles was significantly better than that of the standard and experienced 57-mm ZIS-2 cannons, which were tested in parallel, but did not enter the C-40 armament. The arguments of opponents are the same: the technological complexity of manufacturing the barrel, low survivability, as well as the low efficiency of the fragmentation projectile. But besides that, the then Minister of Arms D.F. Ustinov fiercely hated Grabin and opposed the adoption of any of his artillery systems.

Conical nozzles

It is curious that the conical barrel was used not only in anti-tank guns, but also in anti-aircraft artillery, and in special-power artillery.

So, for 24-cm long-range gun K.3, serially produced with a conventional bore, in the 1942 – 1945 years, several more samples of conical barrels were created, which Kruppa and Rheinmetall worked together to create. For firing from a conical barrel, a special sub-caliber 24 / 21-cm projectile weighing 126,5 kg, equipped with 15 kg of explosive, was created.

The vitality of the first conical barrel was low, and it was too expensive to change the trunks after a few dozen shots. Therefore, it was decided to replace the cylindrical-conical barrel. They took a regular cylindrical barrel with small cuts and provided it with a conical nozzle with a weight of one ton, which was simply screwed onto the regular barrel of the gun.

During the firing, the survivability of the conical nozzle turned out to be about 150 shots, that is, higher than that of the Soviet 180-mm B-1 X-guns (with small cutting). During the shooting in July 1944, the initial speed 1130 m / s and the range 50 km were obtained. In further tests, it turned out that the shells, which had initially passed such a cylindrical part, are more stable in flight. These guns, along with their creators, were captured by Soviet troops in May 1945. The development of the K.3 system with a cylindrical-tapered barrel was carried out in 1945 – 1946 in the city of Zemmerd (Thuringia) by a group of German designers under the leadership of Assman.

By August, 1943, Rheinmetall, produced an 15-cm anti-aircraft gun GerКt 65F with a tapered barrel and a projectile with swept tail. A projectile with a speed of 1200 m / s allowed to reach targets at a height of 18 000 km, where he flew 25 seconds. However, the survivability of the barrel in 86 shots put an end to the career of this miracle cannon - the consumption of projectiles in anti-aircraft artillery is simply monstrous.

Documentation on anti-aircraft installations with a tapered barrel came into the Artillery-Mortar group of the USSR Ministry of Armaments, and in 1947, at the 8 plant in Sverdlovsk, Soviet prototypes of anti-aircraft guns with a conical channel were created. The 85 / 57-mm cannon of the KS-29 cannon had an initial speed of 1500 m / s, and the 103 / 76-mm of the KS-24-cannon was 1300 m / s. For them were created original ammunition (by the way, classified so far).

Tests of guns confirmed the German flaws - in particular, low survivability, which put a final cross on such guns. On the other hand, systems with a conical barrel caliber 152 – 220 mm before the appearance of the C-1957 anti-aircraft missiles in 75 in the year could be the only means of destruction of high-altitude reconnaissance aircraft and single rocket bombers carrying nuclear weapons. Unless, of course, we could get into them.
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  1. dred
    dred 27 December 2011 19: 22
    Well, the Germans burn a loaf.