- Years of issue – 1939 – 1940
- In total, 18994 units were produced.
- Caliber – 50 mm
- Weight in firing position – 12 kg
- Calculation – 2 people
- Rate of fire – 32 rds / min
- The greatest firing range – 800 m
- Direct shot range – 200 m
- Shooting angles:
- Horizontal – 6 °
- Vertical + 45 ° + 82 °
Developing Soviet industry in the 1920s – 1930s, the state constantly took into account the needs of the Red Army. The defense industry developed rapidly. During the first two five-year plans (from 1928/1929 to 1938), colossal work was done to equip the Red Army with new types of weapons and military equipment. The second half of the 1930s was a period of rearmament of artillery with new materiel, including mortars, for the development of which special design bureaus were organized at a number of factories.A particularly large contribution to the creation of mortar weapons was made by the Special Design Bureau No. 4 (SKB-4) at the Leningrad Artillery Plant No. 7 “Arsenal” them. Frunze, led by the outstanding Soviet designer B.I. Shavyrin. Since 1936, he supervised the work and was directly involved in the creation of a number of mortar models that played an important role in the fight against Nazi Germany in the Great Patriotic War.
B.I. Shavyrin was actually able to prove that mortars are not some kind of “surrogate” of artillery used in its absence (as the leadership of the Red Army believed), but an independent type designed to perform combat missions that are difficult, and sometimes impossible to solve with the help of conventional artillery pieces. In his opinion, the company mortar was supposed to become a close-range weapon, which, along with high maneuverability, simplicity of the device and handling it in battle, should have good accuracy of fire.
The 50 mm company mortar was developed at SKB-4 in early 1937. Several prototypes of mortars were tested during the year. At the beginning of 1938, comparative tests of company mortars and automatic grenade launchers took place, as a result of which GAU proposed SKB-4 to modify the 50-mm company mortar “Osa”, after which it was adopted by the Red Army in the same year, under the designation “50-mm company mortar model 1938 “. Its serial production was already mastered in 1939.
The 50-mm company mortar of the 1938 model was intended for fire support of the actions of a rifle company and was used during the war years to destroy or suppress enemy fire weapons and manpower located both openly and on reverse slopes and in shelters. It was created according to the scheme of an imaginary triangle with Stokes-type ignition. The scheme of an imaginary triangle was used in most of the mortars that were in service with the Red Army during the Second World War. The two sides of this triangle are the trunk and the two-legged carriage, and the third side is an imaginary line passing along the ground between the support points of the barrel and the two-legged carriage.
The mortar consisted of a smooth barrel with a breech, a two-legged carriage and a base plate. A membrane-type base plate served as the base for the barrel. The slab consisted of a base sheet, to which stiffeners were welded from below. The recoil force arising from the shot through the plate was transferred to the ground. The distribution of this recoil force over a relatively large area contributed to a decrease in pressure, so the mortar did not go deep into the ground when fired.The change in the firing range in this mortar was carried out both by changing the amount of gases used, and by changing the length of the mine’s path in the barrel. When the striker moved, the volume of the chamber changed. One of the features of the mortar was that it was fired at two fixed elevation angles: 45 ° or 75 °. An elevation angle of 45 ° with a closed remote crane provided the greatest range of fire (800 m), and an angle of 75 ° with an open remote crane provided a minimum range (200 m).The change in the firing range was carried out using a remote crane mounted in the breech of the barrel, through which part of the powder gases was discharged from the barrel bore, changing the pressure of the powder gases to a mine moving along the barrel bore. In the hollow firing pin of the remote crane there were windows through which the powder gases from the barrel bore were directed inside the firing pin and, having passed the firing pin, came out through the hole in the stem of the remote crane. When the crane was turned, the striker, resting with its protrusions on the nut, moved back or forth and opened the windows by a certain amount. To turn the crane to the required firing range, a scale calibrated in meters was used.
When firing at all ranges, only one mortar charge was used. When the remote valve is closed, the initial speed of the mine is 95 m / s, with the valve open – 65 m / s. The mortar rate of fire was 30 rounds per minute.
The two-legged carriage gave the mortar barrel a certain direction, that is, the corresponding angles of vertical and horizontal guidance. It consisted of a bipod with a lifting mechanism and a leveling mechanism, a shock absorber and a swivel with a swivel mechanism. A lifting mechanism was used to give the mortar elevation angles. Its rod was located perpendicular to the rotary mechanism screw.
The leveling mechanism was used to bring the goniometric table of the sight to a horizontal position. The swivel mechanism provided accurate horizontal direction of the barrel and allowed horizontal guidance within 3 °. The shock absorber, consisting of two cylinders, served to soften the shocks transmitted when fired from the barrel to the biped. In a 50-mm company mortar, a mechanical sight was mounted, without optical devices. The ammunition load of a 50-mm mortar of the 1938 model consisted of a cast-iron four-feather fragmentation mine. Soon, to increase the accuracy of fire, it was replaced by a new 50-mm steel fragmentation mortar mine with a six-fins stabilizer.
Life has shown that it is not enough to call the weapon company, battalion or regimental – it is necessary that these weapons organically merge into the unit and, by their presence in it, do not violate the established battle formations, but contribute to the fullest fulfillment of the tasks facing the unit. To make mortars a true weapon of the infantry, capable of accompanying it at all stages of the battle, simple and reliable means were required for transporting it on the battlefield and on the campaign. This work by B.I. Shavyrin instructed the highly qualified designer P.V. Goryachev, who had previously participated in the development of packs and vehicles for the 76-mm mountain cannon, and had this rare design specialty.
Especially for the company mortar (due to its relatively low weight –
12 kg), a human pack was developed that made it possible to carry the mortar on the campaign and on the battlefield on the back of one of the numbers of the mortar crew. This method of transportation turned out to be very convenient: with a company mortar, it was possible to get through wherever a pedestrian would pass – through a forest and a swamp, along narrow winding communication passages, along rocky mountain paths. In the campaign, three company mortars were packed and transported in a special mortar carriage of the 1938 model (MP-38). The ammunition load was carried by the second number of the calculation, two trays (7 minutes in each).
The production of a 50-mm company mortar of the 1938 model was mastered by Plant No. 7
(Leningrad) in 1939, when 1,720 mortars were manufactured. For the 1st – 3rd quarters of 1940, eleven factories planned to manufacture 23105 50-mm mortars of the 1938 model, and by August 1, 1940, 18994 mortars were manufactured. The company mortars of the 1938 model were replaced by the more advanced 50-mm mortar of the 1940 model. 50-mm company mortars of the 1938 model were widely used by the rifle units of the Red Army in the battles on the Khalkhin-Gol River, during the Soviet-Finnish war of 1939-1940, as well as in the initial period of the Great Patriotic War.