- Years of issue – 1944 – 1945
- Total released – no data
- Caliber – 85 mm
- Weight in firing position – 4700 kg
- Barrel length – 5740 mm
- The length of the threaded part – 4550 mm
- Calculation – 7 people
- Travel speed – 35 km / h
- Rate of fire – 20 rds / min
- Maximum firing
range -18,000 Direct fire range – no data
- Shooting angles:
- Horizontal – 360 °
- Vertical – 3 ° + 82 °
During the Great Patriotic War, the 85-mm anti-aircraft gun 52-K of the 1939 model underwent significant modernization aimed at increasing its combat and improving operational characteristics. In 1943, it was successfully tested, created in the design bureau of plant number 8 named. MI Kalinina (Sverdlovsk), a modernized
85-mm cannon model 1939, which received the index “KS-12”. Instead of a barrel, which consisted of a casing and a free tube, this weapon received a high-tech elongated monoblock barrel, and the semiautomatic inertial-mechanical type was replaced by a copier one.
For the gun, a new cradle and a balancing mechanism were developed, an automatic roll speed regulator was introduced, the design of the lifting and turning mechanisms was simplified, an automatic fuse installer was mounted, which made it possible to speed up the preparation of the shot. In addition, a number of individual units and mechanisms have been improved. Thus, the widespread use of the 85-mm anti-aircraft gun in combat conditions proved that the gun must be equipped with a shield cover. At the end of 1944, the ZU-8 platform was also modernized, which received the designation “ZU-13”.On the ZU-13 platform, 85-mm anti-aircraft guns 52-K and KS-12 were installed. Due to the increase in the mass of the powder charge in the shot, the initial velocity of the projectile increased significantly – from 800 to 870 m / s, which increased its power. The newly developed technology for the production of guns used hot and cold stamping, centrifugal casting, automatic welding. During the war, a simplified ZU-11 platform was created and put into production for the 85-mm anti-aircraft gun.Thanks to these measures, the volume of machine tools and fittings and assembly work spent on the production of one gun decreased from 2051.5 man-hours in 1942 to 1360.5 man-hours in 1943. On each cannon, it was possible to save 630 kg of alloy and carbon steels and 51 kg of non-ferrous metals, which made it possible to expand the production of guns accordingly.
In February 1944, this gun, which significantly surpassed the cannon of the 1939 model in terms of firing range, under the designation “85-mm anti-aircraft gun KS-12 of the 1944 model” was put into mass production at the plant No. 8 named after. Kalinin in the city of Sverdlovsk. In 1945, the Red Army received 712 85-mm KS-12 anti-aircraft guns of the 1944 model.