Developer - OKB-9. Project manager - F. F. Petrov.
It was put into service on 23.12.1954 by the resolution of the Council of Ministers of the USSR No. 2474-1185ss.
The prototype was made in 1950. The tests were carried out from 1953 to 1955. Serial production started in 1956.
The Soviet Army at the end of the 1940s required replacement of the 122 mm A-19 (M1931 / 37) cannon, which was developed in a hurry and was produced in small quantities until 1945. The A-19 was considered too heavy and had a too short range of fire to deal with artillery. As a result, the 130-mm M-46 field gun was adopted, but the development of the design bureau under the leadership of Petrov was put into production in small quantities. Subsequently, it was this weapon, which first appeared in the troops in 1955, and received the designation D-74 122 mm field gun.
The D-74 cannon is used for:
- destruction (suppression) of artillery, mortars, and other fire weapons;
- destruction (suppression) of manpower;
- destruction of self-propelled guns and heavy enemy tanks;
- destruction of long-term and field defensive structures;
- suppression of search controls and enemy rear services.
The D-74 barrel is mounted on the same carriage as the D-20 cannon-howitzer - a conventional two-bed carriage with a pallet and a plate designed for hanging the wheels in the firing position. With the help of this plate, the gun was easily and quickly deployed 360 degrees. The long barrel, which had a length of about 50 calibers, was equipped with a two-slot muzzle brake. The 122 mm D-74 cannon has a relatively small shield and is equipped with additional wheels at the ends of the beds, which simplifies maintenance.
The gun consists of a gun carriage and a barrel with a semi-automatic shutter.
The barrel of the gun includes a pipe, a breech, a casing, a clip and a muzzle brake.
The shutter is wedge, vertical, with semiautomatic copying (mechanical) type.
To protect the projectile from falling out of the barrel while loading the gun at high elevation angles, a retainer is provided in the wedge tray, which is automatically recessed at the end of the bolt opening, and does not prevent the ejection of the casings.
For the first loading of the gun, the bolt is opened manually using the bolt handle, which is located on the breech on the right side.
The shot is fired by a trigger located on the breech on the left side.
The carriage consists of: a cradle, recoil devices, an upper machine with a balancing mechanism and guidance mechanisms, a lower machine with a pallet and adjustable beds, suspension and travel, shield cover and sighting devices.
The cradle is cylindrical, cast, consists of two castings paired with each other.
A barrel is placed inside the cradle, which is guided when rolling and rolling back by bronze inserts that are attached to the walls of the cradle. The following are installed on it: a sector of the lifting mechanism, rods of recoil devices, brackets for a copier of a semi-automatic and a sight, as well as a fence with a trigger.
Recoil devices - knurler and recoil brake. The knurler is hydropeumatic, filled with nitrogen or air and steol M. The knurler contains 13.4 liters of liquid. The initial air pressure is 61 atmospheres. Rollback brake - spindle type, hydraulic, has a spring compensator, completely filled with glass M in the amount of 14, 7 liters.
The recoil and recoil brake cylinders are fixed in the barrel clip. The upper machine is the base of the swinging part of the implement. It is a casting, which is fixed in the pins of the lower machine. It contains a shield, balancing and lifting mechanisms. On the left side, the bearing bracket of the pivot mechanism is welded. The sector lifting mechanism is located on the left. The transfer of force to the pinion shaft, which is engaged with the cradle sector, is carried out through a worm and bevel pair. The rotary screw mechanism is located to the left of the implement. One support of its pair is fixed in a bearing, which is located in a bracket welded to the left cheek of the upper machine, the second - in the left frame in the pivot pin.
The balancing mechanism is pneumatic, pushing type. Consists of two columns (left and right). The lower parts of the columns abut against the traverse, the upper ones - against the ball bearings, which were welded to the cradle. The traverse is hinged on the upper machine with the help of pins and axes through an adjustment mechanism. The adjustment mechanism makes it possible to regulate the pressure in the columns when the ambient temperature changes within ± 17, 5 C. To equalize the pressures in the columns, the internal cavities are interconnected by a pipe through a valve device. The balancing mechanism is filled with air or nitrogen. Normal pressure at maximum elevation angle is 53 atmospheres ± 5 atmospheres. In order to ensure the normal operation of the collar, M steol is poured in a volume of 0.15 liters with the addition of 20-30 grams of graphite P.
The lower machine is the base for the rotating part of the cannon. Bases are attached to the lower machine on hinges and a casing with a bearing housing is welded. The half-axles of the undercarriage of the gun are placed inside the machine, torsion bushings are inserted into the half-axles, which are connected to the torsion bars. Their other ends enter with their splines into cranks located in the bearing housing.
A pallet is installed on the lower machine, which is a support in the combat position, which ensures the stability of the gun during a shot. To transfer the weapon between the stowed and firing positions, there is a hydraulic jack installed in the traverse of the pallet. The pallet in the stowed position is folded up and engages with the cradle grips. The pallet in this form secures the trunk during transportation.
Adjustable beds - welded, box-shaped. Both beds are the same. The hinges that connect the beds and the lower machine by means of pins are welded to the front ends of the bed boxes. Winter openers are welded to the rear ends of the frame boxes, in which there is one through hole, which serves for the eccentric rollers of the folding openers for summer use.
An air brake receiver is installed inside the left frame. On the articulated guides, on each bed there is one driven light opener, which are used only in winter conditions when shooting from a bar. This ensures the stability of the gun in the horizontal plane. The beds in the stowed position are fastened with a union tie to each other. The pivot beam, which is fixed between the beds with the help of special brackets with grips, is used to connect the gun to the tractor. The swivel beam in the firing position leans back on a special hinge and locks on the beds. Trunk rollers and rack jacks are reinforced on the outside of the trunk of each frame.
Rack jacks are used to facilitate lifting the implement trunk during coupling (uncoupling) with the tractor and setting on the pedestal rollers. In addition, to transfer the gun from the traveling to the firing position and vice versa. The pedestal rollers are designed for rolling the D-74 over short distances, as well as turning 360 ° on a ball bearing. Summer folding openers are used to support the trunk of the gun when firing from soft ground. Summer openers in the stowed position and when firing from winter openers are folded back to the frame boxes and locked by means of handles through eccentric rollers.
Suspension and travel. For the D-74 cannon, YaAZ-200 wheels with GK 1200x20 tires are used. The hubs of the left and right wheels differ in the direction of the threads on the studs, which are intended for fastening the wheels. Shoe brakes are located inside the wheel discs. The braking of the wheels of the gun is carried out using a manual or pneumatic drive. Torsion cushioning during wheel firing is not disabled.
Sights - mechanical sight S-71 with art. panorama and OP-2 (direct aiming sight). Both sights are located on the left side of the cradle and are attached to the bracket. The OP-2 sight is permanently attached to the cannon and is removed only during a long transition or during long-term storage of the D-74. Mechanical S-71 is permanently fixed; the panorama is filmed for storage in a special box. Sights for firing at night are supplied with Luch-S71M lighting.
The right and left half of the shield make up the shield cover, which is attached to the upper machine. In addition, the cover includes a movable flap fixed to the cradle, a lower flap fixed to the lower machine.
A railing with a descent is attached to the left side of the cradle. On the fence there is a handle for recocking the striker, a trigger mechanism, a recoil indicator ruler and a slider, as well as a knurling test schedule.
The types of D-74 ammunition used are basically similar to those used by other 122-mm artillery systems with cartouche loading, however, the propellant charge power may vary. The maximum firing range is 24 thousand meters. The D-74 cannon, as is customary with Soviet artillery systems, can be used to destroy armored targets. To do this, use an armor-piercing projectile weighing 25 kilograms with a solid core, capable of penetrating 185 mm armor at a distance of one thousand meters. However, today ammunition of this type in artillery systems is considered obsolete and is practically not used.
Although the D-74 in the SA unit was received in limited quantities (it is possible that they are still in reserve), most of the guns were exported to Vietnam, Egypt, China, Cuba and North Korea. One batch of cannons was even delivered to Peru, and the D-74 cannon made such a strong impression on the Chinese that they set up their own similar cannons, designated the 122-mm Type 60 cannon.
The performance data of the 122 mm D-74 corps gun:
Caliber - 122 mm;
Barrel length - 6450 mm (52, 9 caliber);
Firing range: direct fire - 850 m (1040 m), OFS - 24 thousand m;
The initial velocity of the projectile is 885 m / s;
Horizontal guidance angle - 58 degrees;
Angle of vertical guidance - from -5 to +45 degrees;
Loading - separate-sleeve;
Sighting rate of fire - up to 7 rounds per minute;
Sights: direct aiming sight OP-2-97 (OP4-97, OP4M-97, OP4M-97K), mechanical sight S-71 with artillery panorama;
Weight in firing position - 5, 5 thousand kg;
Weight in the stowed position - 5, 55 thousand kg;
Barrel weight with muzzle brake and bolt - 2336 kg;
Shutter weight - 96 kg;
Length in the stowed position - 8690 (9875) mm;
Width in the stowed position - 2400 (2350) mm;
Height in the stowed position - 2000 mm;
The height of the line of fire - 1220 mm;
The normal rollback length is 910 mm;
Maximum rollback length - 950 mm;
The volume of fluid in the rollback brake is 14.7 liters;
The initial pressure in the reel - 61 kgf / cm2;
The volume of the liquid in the knurler is 13.4 liters;
Transition time from traveling to combat position - from 2 to 2, 5 minutes;
Calculation - 10 people;
Traction - an artillery tracked tractor or truck (6x6);
Towing speed: off-road - 15 km / h, on cobblestones - 30 km / h, on the highway - 60 km / h.
Ammunition:
High-explosive fragmentation projectile.
The initial speed is 885 m / s.
Weight - 27.3 kg.
Armor-piercing projectile.
Weight - 25 kg.
Armor penetration (at an angle of 60 degrees):
At a distance of 500 m - 170 mm;
At a distance of 1000 m - 160 mm;
At a distance of 1500 m - 150 mm;
At a distance of 2000 m - 140 mm.
The countries in which it is currently in service are Vietnam, Egypt, Peru, North Korea, China, Cuba.
