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2B1 Oka

Soviet Union (1957)
Picture of 2B1 Oka Self-Propelled Artillery (SPA)

The ultimately-abandoned 2B1 Oka tracked self-propelled artillery system mounted a massive 420mm main gun barrel.

Detailing the development and operational history of the 2B1 Oka Self-Propelled Artillery (SPA).  Entry last updated on 3/3/2018. Authored by Staff Writer. Content ©

The 2B1 "Oka" was a short-lived, heavy-class, self-propelled gun system developed by the Soviet Union at the height of the Cold War. Such large-caliber guns had proven the norm for decades and found renewed importance during World War 1 and into the interwar years leading up to World War 2. The French, British, Americans and Germans all became keen on the prospects of large-caliber guns and, while their tactical use was severely restricted, their simple existence often proved a psychological tool against civilian populations they might target.

A prototype of the 2B1 system was unveiled in 1957 at the legendary Kirov Plant in St. Petersburg, Russia. The 2B1 Oka's operating principle was relatively simple - to lob large explosive projectiles against target areas deep within enemy territory - as far away as 45 kilometers according to her design. The 2B1 made use of a mammoth 420mm cannon installation mounted to a tracked hull. The gun mount sat at the center of the hull roof. Eight double-tired road wheels dotted the track sides with each pair heavily strutted to counter both weight and recoil. The drive sprocket was mounted to the front of the track system with the track idler at the rear and at least four track return rollers were used. Heavy duty recoil struts straddled the main gun at its base and the gunnery crew would have operated in the elements for no cover was afforded - the 2B1 was essentially a rolling gunnery stage and nothing else. No muzzle brake was fitted to the smooth barrel system which was not tapered in any way. A single V12 diesel-fueled engine would have supplied up to 700 horsepower.
On paper, her self-propelled nature would have made her somewhat mobile and her lethal reach could have proven devastating but, in practice, there emerged too many deficiencies in her design. The long gun barrel made even basic transport of the vehicle highly impractical and the violent recoil of such a weapon stressed the gun mount, hull and track components to their extremes - leading to consistent failures of said systems in testing. Even the required large 420mm projectiles made any attainable sustained rate-of-fire impossible to continue for stretches by the seven-man crew. The single engine worked against the vehicle's weight of 55 tons and would have made her extremely limited tactically - especially when attempting to go off road. The end result became a machine of war that was more trouble than it was worth, resulting in its cancellation in 1960.

Like the Americans, the Soviets elected instead to focus financing and resources towards the development of newer battlefield missiles that could do the same job as the 2B1 Oka while reaching out to distances that would have proven impossible by projectile-based systems. At any rate, the 2B1 Oka became a novel attempt that was destined to fall to the pages of military history.

Supported Mission Types:
Troop Transport
Infantry Support
High Mobility
Tank Destroyer
Special Forces
Towed Artillery
Self-Propelled Artillery
Rocket Artillery
Airspace Denial
Special Purpose
National Flag Graphic
Origin: Soviet Union
Year: 1957
Type: Self-Propelled Artillery (SPA)
Manufacturer(s): Leningrad Kirov Plant LKZ - Soviet Union
Production: 1
Global Operators:
Soviet Union (cancelled)
Measurements and Weights icon
Structural - Crew, Dimensions, and Operating Weights:
Unless otherwise noted the presented statistics below pertain to the 2B1 Oka model. Common measurements, and their respective conversions, are shown when possible.




9.84 ft

3 m


Tons (US Short)
61 t

55,300 kg

121,916 lb

Engine icon
Installed Power - Standard Day Performance:
1 x V12 diesel engine developing 700 horsepower.
Armament and Ammunition:

1 x 420mm main gun barrel.

Dependent upon ammunition carrier.
Optional Systems / Capabilities:

Nuclear-Biological-Chemical (NBC) Protection: None.
Nightvision (NV) Equipment: None.
Variants: Series Model Variants
• 2B1 "Oka" - Base Series Designation