This weapon was created by mounting the Army 85 mm/52 (3.3") Pattern 1939 AA gun on the 34-K 76.2 mm (3") gun mount, with testing taking place from June to August 1941. The same gun was used on the T-34/85 tanks as ZIS-S-53. Production of the naval version started in 1942 at Factory No. 8 in Sverdlovsk with four guns being completed that same year. Curiously, this mounting was not officially accepted into service until June 1946. A total of 320 guns were made at Sverdlovsk from 1942 until 1949. Production was then transferred to Factory No. 92 in Gorky, where another 284 mounts were made during the 1950s. By 1991 thirty-seven 90-K mounts were still on hand in the Soviet Navy.

In 1946 a twin mount was created by placing two 90-K barrels in one cradle and this was accepted into service in December 1946 as 92-K. Between 1946 and 1953 some 102 of these twin mounts were built. These mountings were controlled by Soyuz-30bis system.

In 1944 a single turret mount MK-85 was created by TsKB-34. The turret was designed for use on the River gunboats, but was also used on some of the Pr.30bis destroyers. The mount was accepted into service in 1946 and was in production from 1946 to the mid 1950s. The turret was similar in construction to the contemporary tank turrets and used the ZIS-S-53 tank gun (similar to the 90-K gun) but modified for high angle firing.

Now obsolescent, this gun is still used on unmodified Skoryy class destroyers and on PRC small craft such as Kronstadt-type submarine chasers.

Construction consists of barrel, lose liner, breech casing and breech mechanism. The breech is vertical blade type, with spring-type semi-automatics. The 1942 project envisioned using electrical firing mechanisms, but they were never installed and the guns operated in manual mode throughout its service.

Gun Characteristics

Designation 85 mm/52 (3.3") 90-K
Ship Class Used On
  • 90-K
    • Kaganovich and Kalinin (Pr.26bis) light cruisers, Ognevoy class (Pr.30)
    • Skoryy Class (Pr.30bis) and all other modifications of Pr 30 destroyers
    • Some Yastreb class (Pr.29) patrol ships, Artillerist class (Pr.122) sub chasers and other misc. ships
  • 92-K
    • Some Pr. 30K and Pr.30 Bis destroyers, Pr.1190 monitors
  • MK-85
    • BK-521 class (Pr.186) Small River gunboats, some Pr.30 Bis destroyers, Riverine Armored MTBs
Date Of Design 1941 (modernized)
Date In Service 1942 (90-K)
Gun Weight 2.07 tons (2.1 mt)
Gun Length oa 174.61 in (4.435 m)
Bore Length 163.21 in (4.146 m)
Rifling Length 137.64 in (3.496 m)
Grooves 28
Lands N/A
Twist N/A
Chamber Volume 240.4 in3 (39.4 dm3)
Rate Of Fire 15 - 18 rounds per minute


Type Fixed
Weight of Complete Round AA (O-365): 55.56 lbs. (25.2 kg)
Distance Grenade (O-365M): 55.65 lbs. (25.24 kg)
FRAG (O-365K): 56.31 lbs. (25.56 kg)
AP (BR-365): 55.56 lbs. (25.2 kg)
Projectile Types and Weights AA (O-365): 20.28 lbs. (9.2 kg)
Distance Grenade (O-365M): 20.37 lbs. (9.24 kg)
FRAG (O-365K): 20.03 lbs. (9.54 kg)
AP (BR-365): 20.28 lbs. (9.2 kg)
Bursting Charge AA (O-365): 1.46 lbs. (0.66 kg)
Distance Grenade (O-365M): 1.42 lbs. (0.646 kg)
FRAG (O-365K): 1.63 lbs. (0.741 kg)
AP (BR-365): none (?)
Projectile Length AA (O-365): 3.4 calibers
Distance Grenade (O-365M): 3.4 calibers
Propellant Container Type and Weight Cartridge: 35.27 lbs. (16 kg)
Propellant Charge 5.47 lbs. (2.48 kg)
8.05 lbs. (3.65 kg)
Muzzle Velocity AA (O-365): 2,600 fps (792 mps)
Distance Grenade (O-365M): 2,600 fps (792 mps)
FRAG (O-365K): 2,575 fps (785 mps)
AP (BR-365): 2,600 fps (792 mps)
Working Pressure 2535 kg/cm2
Approximate Barrel Life 1600 rounds
Ammunition stowage per gun 400 rounds


Maximum ranges with radious shells
Shell Distance
AA Ceiling Ballistic
20.3 lbs. (9.2 kg) AA (O-365) 24,323 yards (22,241 m) -
20.0 lbs. (9.54 kg) FRAG (O-365K) - 17,000 yards (15,565 m)
20.3 lbs. (9.2 kg) AP (BR-365) - 16,750 yards (15,309 m)

Mount/Turret Data

Designation Single Mount: 90-K
Single Turret: MK-85
Twin Mount: 92-K
Weight Single Mount: 8.74 tons (8.88 mt)
Single Turret: N/A
Twin Mount: 12.25 tons (12.44 mt)
Elevation Single Mount 90-K: -5 / +85 degrees
Single Turret MK-85: -8 / +77 degrees
Twin Mount 92-K: -5 / +85 degrees
Rate of Elevation Single Mount 90-K: Up to 8 degrees per second
Single Turret MK-85: N/A
Twin Mount 92-K: 10 degrees per second
Train 360 degrees for all
Rate of Train Single Mount 90-K: up to 12 degrees per second
Single Turret MK-85: N/A
Twin Mount 92-K: 18 degrees per second
Gun Recoil Single Mount 90-K: 15.4 - 18.7 in (39 - 47.5 cm)
Single Turret MK-85: 11.0 - 12.6 in (28 - 32 cm)
Twin Mount 92-K: 15.4 - 18.7 in (39 - 47.5 cm)


Data from:

  • "The Naval Institute Guide to World Naval Weapon Systems 1991/92" by Norman Friedman
  • "Sovetskie Boevye Korabli 1941-45: IV Vooruzhnie" (Soviet Warships 1941-45: Volume IV Armament) by A.V. Platonov
  • "Entsiklopedia Otechestvennoi Artillerii" (Encyclopedia of Fatherland (Russian) Artillery) by A.V. Shirokorad

Special help from Vladimir Yakubov