Modern 16-inch guns would not fit Victoria's short 16.25-inch mountings

Could a twentieth-century 16-inch gun replace HMS Victoria's 16.25-inch guns?

Probably not; the later gun's much greater length and mounting requirements would exceed the old installation's limits.

Similar bore diameter does not make two weapons interchangeable. Later 16-inch weapons were far longer than Victoria's 16.25-inch guns, just as Furious required a shortened 18-inch weapon to fit its constrained hull.