Yamato's maximum range versus effective range

Did Yamato's 18-inch guns have a meaningful range advantage over the US Navy's 16-inch/50 guns?

They had a theoretical maximum-range advantage, but their effective ranges were broadly similar because hit probability, rate of fire, and correction time governed practical engagements.

Yamato's 18-inch guns are credited with a maximum range of about 26 miles at 45 degrees elevation, compared with roughly 24 miles for the US 16-inch/50. Effective range depends on the chance of hitting, with five percent used here as the working threshold. The American figures give about ten percent at 20,000 yards, a little over 18 kilometres, and 2.7 percent at 30,000 yards, about 27 kilometres. The figures for the two weapons were recorded differently, so placing both effective ranges around 25 kilometres or 16 miles remains an approximation. Guns larger than 16.5 inches also incur penalties in firing rate and the time needed to correct their fire. That combination underpins the judgment that 16.5 inches was near a practical optimum, while an existing American 16-inch system offered little reason to change calibre.