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In 1954 development of a quad mount using the same ZIF-74 barrels was begun. This mounting was designated as ZIF-75. The prototype mounting was made in 1956 and trials lasted until 1960. The trials revealed that that maximum burst was only 50 rounds, after which the gun had to be cooled down for 1.5 minutes. A further problem was the long reload time, some 2.5 to 3 minutes for all 4 barrels even with four reloaders. The constant burst time until the ammo ran out was 28-30 seconds. A total of 54 mounts were built. These weapons had significant operational problems, most of them connected to the fact that they were in open mounts, which caused problems for ships operating in the Arctic Ocean and meant that they lacked NBC protection. The guns themselves were clip fed, which lowered down their practical rate of fire. However, the main problem was that the barrels were air cooled, which led to overheating problems even for short bursts. The guns could fire only 50 shots per barrel before water from a fire hose had to be run through the barrel to cool it down. All of this prompted the navy to request the design of the completely new mount in 1956 which eventually became AK-725. The barrel was of monobloc construction with flash suppresser. The automatic mechanism was recoil-operated. |
Quad 57 mm/81 ZIF-75 mountings on a Krupny-class
destroyer
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