Visibility limited the practical value of 8-inch cruiser range

When did additional gun range cease to be useful because a ship could not find or see the target?

Before radar, visibility and fire control often made the 8-inch gun's extra range less useful than the 6-inch gun's higher volume of fire.

An 8-inch gun could throw a shell farther than a 6-inch weapon, but range alone did not produce hits. Pre-radar visibility and target location often became the binding limits. If a cruiser could not see or track an opponent at the extra range, the heavier gun's reach offered little practical benefit. British interest in 6-inch cruisers therefore reflected the value of putting more shells onto targets that fire-control systems could actually engage.