AK-257

The AK-257 is a Soviet 57mm naval gun, originally a land ZIF-31 L/70 57mm (Type 66/76) cannon.

During the early 1950s, development began of naval versions of the 57x348mmSR 70 calibre weapon which had entered service with the Soviet army in 1950 as the S-60.

This was to be a supplementary weapon for larger warships and as the main gun armament for minesweepers and auxiliaries.

The twin gun version, ZIF-31, appears to have entered service with the Project 264 Minesweepers (T58 class) and the Project 310 (Don class) submarine support ships in 1958.

In smaller warships these mountings were sometimes associated with MR-103 and in larger ones with the Yakhond (Hawk Screech) radar.