How dangerous is a modern destroyer using only guns compared with gun-heavy warships of the past?
Short answerIt is much more accurate but has less sustained firepower, and would be badly mismatched against a battleship.
NotesA modern destroyer's gun benefits from far better sensors, fire control, and accuracy than historic surface combatants enjoyed. Its weakness is the limited volume and duration of gunfire available once missiles are excluded. Against another destroyer, those advantages may still make it dangerous, while a cruiser comparison depends on whether the opponent is light or heavy. Sending the same ship into a gun duel with a battleship would be deeply unfavorable, showing why weapon effectiveness cannot be separated from magazine depth and target resilience.