Derivatives / Succeeded by 2001 Mk.8 Mod 1 4.5 inch Specifications 4crew 113caliber (mm) 25Rate of fire (round/min) 22range (km) Used by 1973 Type 82 Bristol class guided-missile destroyer DDG 11974 Type 21 Amazon class frigate FF 11977 Hercules class guided-missile destroyer DDG 11989 Inhaúma class corvette FS 12004 Hercules class command ship LCC 1 In Service Royal Navy Pakistan Navy Argentine Navy Brazilian Navy