In the second half of 1943, after the failure of the summer offensive on the Eastern Front, Germany was forced to go over to strategic defense. In the face of ever-increasing pressure in the East and an increase in the scale of bombing by British and American aircraft, it became quite obvious that the military industry of the Reich, even taking into account the growth in production volumes, does not have time to meet the needs of the front. Although German anti-aircraft artillery was rightfully considered the best in World War II, the troops were sorely lacking anti-aircraft cover. This situation was further aggravated in 1944 after the Allied landings in Normandy. Having lost air superiority, the Luftwaffe command was forced to send a significant number of experienced fighter pilots to squadrons specialized in intercepting British and American heavy bombers, whose armada methodically destroyed German cities and industrial enterprises. The problem of protection against devastating air raids was aggravated by the shortage of aviation gasoline. Even with serviceable aircraft, German fighters did not always have anything to refuel. The lack of fuel led to a radical reduction in flight hours at aviation schools, which could not but negatively affect the level of flight training of young pilots. As follows from the memoirs of the German soldiers who survived in the meat grinder of World War II, in 1944 they developed the so-called "German look", when the front-line soldiers, even without being in the front line, looked anxiously at the sky in anticipation of attacks by attack aircraft. Having lost an effective fighter cover, the German ground forces demanded more rapid-fire anti-aircraft guns, and in the current situation, various ersatz anti-aircraft guns and systems captured in the occupied countries went into action.
The SS troops and the Wehrmacht, in addition to 20-mm anti-aircraft guns produced in Switzerland and Germany, had a significant number of captured installations, as well as 20-mm anti-aircraft guns, converted from aircraft cannons. A typical example of the German anti-aircraft system created in the second half of the war was the triple-mounted installation, which used the MG.151 / 20 20-mm aircraft cannon. This weapon with automatics working on the use of the recoil of a movable barrel, with which the bolt is firmly engaged during the shot, was created by the designers of the Mauser Werke company on the basis of the 15-mm MG.151 / 15 aircraft machine gun. In connection with the increase in caliber to 20 mm, not only the barrel, which became shorter, but also the chamber, were changed. I also had to use a more powerful rear spring buffer, new tape receiver and sear.
For firing from the MG.151 / 20, 20x82 mm ammunition was used. Projectile weight: from 105 to 115 g. Initial speed: 700-750 m / s. In addition to armor-piercing incendiary, armor-piercing incendiary-tracer, fragmentation-incendiary-tracer, the ammunition load also included a high-explosive projectile containing 25 g of RDX-based explosives. When a 20-mm high-explosive projectile hit the Il-2 armored hull, in most cases it broke. The hit of a high-explosive projectile in the keel or plane of a Soviet attack aircraft, as a rule, caused the destruction of these structural elements, which meant the termination of controlled flight. The ammunition capacity of the 151/20 cannon when firing at air targets was originally equipped with a cartridge belt, which contained only 20% of armor-piercing shots: 2 high-explosive, 2 fragmentation-incendiary-tracer and 1 armor-piercing incendiary or armor-piercing tracer. However, towards the end of the war, due to the lack of special shells, the share of cheaper armor-piercing tracer shells in the tape began to be 50%. An armor-piercing tracer projectile at a distance of 300 m, when hit at an angle of 60 °, could penetrate 12 mm of armor.
MG.151 / 20 were produced in motor-cannon versions, in synchronous and wing versions, as well as for use in defensive turret installations. The mass of the gun was 42 kg, the rate of fire was 750 rds / min. Production of the MG.151 / 20 aircraft gun began in 1940 and continued until the end of the war. It was widely used as the main armament for Bf 109 and Fw 190 fighters of various modifications, as well as fighter-bombers, night fighters and attack aircraft, and was installed in mechanized and manual turrets on bombers. In the non-mechanized turret version, the MG 151/20 gun was equipped with two handles with a trigger and a frame sight placed on the bracket.
In the first half of 1944, the Luftwaffe had about 7,000 MG.151 / 20 cannons and more than 5 million shells for them. The first 20 mm MG.151 / 20 cannons adapted for anti-aircraft fire were turrets dismantled from damaged bombers. Such installations were used to provide air defense of field aerodromes. Turret MG.151 / 20 were mounted on improvised supports in the form of logs or pipes buried in the ground. Sometimes an armored shield was placed on an aircraft gun used as an anti-aircraft gun.
However, the synchronous and wing versions, which were part of the strike weapons of fighters and attack aircraft, could not be installed on anti-aircraft turrets without serious revision. Unclaimed 20mm aircraft guns were converted for ground use in arms factories and large repair shops. The main changes were made to the reloading device and the trigger. The existing electric launch systems and pneumatic reloading mechanisms were replaced by mechanical parts that ensure continuous fire when mounted on anti-aircraft installations. Judging by the specimens preserved in museum exhibitions and captured in photographs from the Second World War, several versions of single-barreled and twin anti-aircraft guns were created using MG.151 / 20 aircraft cannons.
The most common anti-aircraft gun using 20-mm MG.151 / 20 cannons was a horizontal-mounted installation on a pedestal support known as a 2, 0 cm Flakdriling MG 151/20 or Fla. SL.151 / 3. Mass production of this installation began in the spring of 1944, and it structurally and externally had much in common with the ZPU, which used 15-mm MG.151 / 15 machine guns.
Three shell boxes were attached to the rotary pedestal support below the cannons. The front box contained a tape with 400 rounds, two side ones - 250 each. This feature of storing the ammunition was associated with the inconvenience of equipping the front box in comparison with the side ones. Some anti-aircraft guns had flame arresters that reduced the muzzle flame that blinded the shooter.
The aiming of the built installation at the target was not mechanized. The shooter, leaning against the shoulder supports, had to make significant efforts to aim the gun, the mass of which with ammunition exceeded 200 kg. Although the designers tried to balance the guns in the horizontal plane, the angular aiming speed was small, and the inertia when rotating on the bollard was very significant. Nevertheless, an anti-aircraft gun with a rate of fire of more than 2000 rds / min for aircraft flying at low altitude posed a serious danger. The big advantage of the "three-barrels" which had a tape feed in comparison with the 20-mm quadruple MZA 2, 0 cm Flakvierling 38, was the ability to fire in long bursts of longer duration. For this, only one shooter was required, while a crew of eight was required to service the quadruple magazine-loaded installation.
The exact number of built installations of 2, 0 cm Flakdriling MG 151/20 received by the troops is now impossible to establish, but judging by the number of photographs where they are captured, a lot of these anti-aircraft guns were released. Three-barreled 20-mm anti-aircraft guns were mounted both permanently for object air defense, and on various armor, auto and railway equipment, including armored air defense trains with them.
Half-track armored personnel carriers of the SdKfz 251 family were most often used as an armored chassis for accommodating the 2, 0 cm Flakdriling MG 151/20. This vehicle was created in 1938 by Hanomag on the basis of the Sd Kfz 11 artillery tractor, and was produced in series until March 1945.
Initially, anti-aircraft guns were placed on armored personnel carriers with an open rear platform. With a good view, the shooter was protected from bullets and shrapnel only by an armored shield in front. From October 1944 to February 1945, the German industry managed to produce approximately 150 ZSU Sd. Kfz.251 / 21 with built-in cannon installations. The crew of an open top ZSU in a circle was covered with armor with a thickness of 8 to 14, 5 mm. The gun mount itself was placed in an armored box.
If necessary, the gunner was able to fire not only at air, but also at ground targets. According to American reports on the fighting, Sd. Kfz.251 / 21 on the Western Front were very often used to support ground forces. In terms of their characteristics, the Sd. Kfz.251 / 21 self-propelled anti-aircraft guns can be considered one of the most successful German models on a half-track chassis. This ZSU, with a relatively low cost, and not bad indicators of mobility and maneuverability, had acceptable firepower. Nevertheless, the Germans did not have time to build many anti-aircraft self-propelled guns of this type. ZSU Sd. Kfz.251 / 21 appeared too late, and did not have a noticeable effect on the course of hostilities. Also, a number of sources mention that the built-in 20-mm installations were mounted on the three-axle reconnaissance armored vehicles M8 Greyhound captured from the Americans. However, it is unlikely that they managed to release many such ZSUs.
After Italy's surrender in September 1943, a significant part of the equipment and weapons of the Italian army was at the disposal of the Wehrmacht. In general, the Italian 20-mm anti-aircraft guns fully corresponded to the then requirements for small-caliber anti-aircraft guns and therefore were used in German air defense units on a par with installations of their own production.
In 1935, as part of the terms of reference issued by the technical department of the Italian Ministry of Defense, Breda Meccanica Bresciana, based on the French 13, 2-mm Hotchkiss Мle 1930 machine gun, created a universal 20-mm Cannone-Mitragliera da 20/65 modello 35 installation, also known as Breda Modèle 35. which used the cartridge "Long Soloturn" - 20x138 mm. The same ammunition was used in German high-speed riflemen: 2.0 cm FlaK 30, 2.0 cm Flak 38 and 2.0 cm Flakvierling 38.
In the Italian army, the 20-mm "Breda" was used as a light anti-tank and anti-aircraft gun. An armor-piercing projectile weighing 120 g, accelerating in a 1300 mm long barrel (65 calibers) to a speed of 840 m / s at a distance of 200 meters, could penetrate 30 mm homogeneous armor when hit at a right angle.
The food, as in the French machine gun, came from a rigid belt clip for 12 shells. The clip was fed from the left side, and as the cartridges were consumed, it passed through the receiver, dropping out on the right. Rate of fire - 500 rds / min. A well-trained crew could develop a combat rate of fire up to 150 rds / min. Installation weight - about 340 kg. Vertical guidance angles: from -10 ° to + 80 °. With the separation of the wheel drive, it was possible to fire in the 360 ° sector.
The versatile Breda Modèle 35 is widely used. As of September 1942, the Italian armed forces had about 3,000 such installations. They were actively used in hostilities in North Africa and Sicily. Very often, Italian 20-mm anti-aircraft guns were mounted on various vehicles. For the object air defense and the naval forces, more than 200 units were released on a stationary rotary carriage. The same installation was subsequently placed on railway platforms.
Captured in Italy 20-mm machine guns "Breda" were used in the Wehrmacht under the designation Breda 2, 0 cm FlaK-282 (i). The production of these anti-aircraft guns continued after September 1943 in the northern territories of Italy controlled by the Germans; in total, the Nazis had at least 2,000 such anti-aircraft guns at their disposal. In addition to the armed forces of Nazi Germany, the Italian 20-mm MZA were actively used by the Finnish army.
After Italy entered the war, the army and navy faced an acute shortage of MZA. The 20-mm Breda Modèle 35 assault rifles were not produced in sufficient quantities. In view of this, it was decided to additionally purchase for the Italian armed forces the 20-mm Cannone-Mitragliera da 20/77 cannons manufactured by Scotti for foreign customers. This 20-mm anti-aircraft gun was created jointly by Scotti and Isotta Fraschini with the assistance of the Swiss Oerlikon in 1936. In the Italian Navy, this weapon was called the 20 mm / 70 Scotti Mod. 1939/1941.
The mass of the installation on a tripod-wheeled machine in the firing position after separation of the wheel travel was 285 kg. When installing the tripod on the ground, there was the possibility of a circular fire. Vertical guidance angles: from -10 ° to + 85 °. Products of firms "Breda" and "Scotty" fired with the same ammunition, and were practically equal in ballistic characteristics. The first version of the 20-mm anti-aircraft gun "Scotty" was loaded with rigid tape-clips for 12 rounds. Later, variants with a 20-charge drum and with a belt feed appeared. The installation with a tape feed and a box for 50 shells had a rate of fire of 600 rds / min and could produce up to 200 rds / min.
In addition to installations on a wheeled-tripod machine, a number of Scoti anti-aircraft guns were mounted on pedestal carriages. The gun on a pedestal carriage was equipped with a counterbalancing system, which made it possible to carry out horizontal and vertical guidance manually without excessive physical effort.
In Milan, at the factory of Isotta Fraschini, which also produced expensive cars, more than 500 20-mm Scotti assault rifles were assembled. Until September 1944, the Italian army actively used them in hostilities. In the fall of 1944, German troops captured about two hundred MZA Cannone-Mitragliera da 20/77, and used them under the designation 2.0 cm Flak Scotti (i).
In addition to their own and Italian 20-mm anti-aircraft guns, the Germans had a significant number of samples captured in other countries at their disposal. Among them, a very successful Danish 20-mm anti-aircraft gun M1935 Madsen on a universal machine with a detachable wheel travel stands apart.
There was also an option on a cruciform anti-aircraft gun carriage with a wheel drive. A small-caliber Danish cannon chambered for a 20x120 mm cartridge, according to the principle of automatic operation, repeated Madsen's infantry machine gun of a rifle caliber with a short barrel stroke and a swinging bolt. The air-cooled barrel was equipped with a muzzle brake. Food was carried out from box magazines for 15 or drum magazines for 30 shells. 20-mm automatic cannon on a universal machine, in the second half of the 30s was popular with foreign buyers and was widely exported. The baptism of fire of the 20-mm M1935 Madsen installations took place during the Soviet-Finnish winter war.
The anti-aircraft gun on a universal machine had a record low mass for its caliber, its weight in a combat position was only 278 kg. Rate of fire - 500 rds / min. Combat rate of fire - up to 120 shots / min. The effective firing range at air targets was up to 1,500 m. The ammunition load included shots with an armor-piercing (154 g), armor-piercing tracer (146 g), fragmentation (127 g) projectile. According to the reference data, an armor-piercing projectile with an initial speed of 730 m / s, at a distance of 500 m along the normal could penetrate 28 mm of armor.
After the occupation of Denmark, Norway and the Netherlands, the Nazis had at their disposal several hundred 20-mm Madsen anti-aircraft guns. The occupation authorities continued the production of anti-aircraft guns and ammunition for them at Danish enterprises. However, in order to save money, the Germans abandoned the production of rather complex universal wheel-tripod machines and installed 20-mm M1935 Madsen assault rifles on swivels, which, in turn, were attached to the decks of warships, the bases of various mobile platforms or on the concreted stationary positions of the Atlantic Wall. … Initially, the 20mm Madsens were used by the Hungarian and Romanian armies on the Eastern Front. However, after parts of the Red Army entered the territory of Germany, all German reserves were mobilized, and Danish-made installations with ammunition non-standard for the Wehrmacht began to be used against Soviet aviation.
