Comparing British and American 6-inch cruiser guns

Was the British Mark 23 6-inch gun better than the American 6-inch/47 fitted to Brooklyn- and Cleveland-class cruisers?

They were broadly comparable; the particular mounting, shell, and firing conditions matter more than the small differences in headline performance.

The British Mark 23 and American 6-inch/47 are judged broadly comparable in capability. Their high-explosive shells differ by only a few pounds, and rate of fire depends on the gun variant and turret arrangement. Published maximum ranges also use different elevations and ammunition: the American figure quoted here uses a 130-pound armour-piercing shell, while the British figure uses a lighter high-explosive shell. Small differences in muzzle velocity or headline range therefore do not establish a decisive advantage for either weapon.