アルバム 15 写真 420mm2B1岡自走砲-モルタル
Photo galery of a 420mm 2B1 Oka Self-Propelled Gun-Mortar, 2B1 Oka (Russian: 2Б1 Ока) is a Soviet 420 mm self-propelled gun. 2B1 is its GRAU designation. An experimental model was ready in 1957. Its chassis (Object 273), was designed and built by the Kirov Plant. Its 20 meter barrel allowed it to fire 750 kg rounds up to 45 km. Due to its complexity of loading it had a relatively low rate of fire—one round every five minutes. Field tests showed various drawbacks of the entire design (the recoil was too strong for many components: it damaged drive sprockets, tore the gear-box away from its mountings, etc.) and the sheer length rendered it incredibly difficult to transport.