Later the 12.7 mm DShK 1938/46 heavy machine gun or 14.5 mm KPV heavy machine gun replaced the 7.62 mm SGMB medium machine gun in the front while an additional 7.62 mm SGMB medium machine gun was mounted on the rear.
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Detailed trials were conducted in the Black Sea area, and it was accepted in service in 1957 with production beginning that year.