Did Austro-Hungarian or other navies use tracer rounds in destroyer or main guns during the First World War?
Short answerThe speakers know of no normal main-gun practice of this kind. They associate tracer with machine guns and later automatic antiaircraft weapons whose higher rate of fire made it useful.
NotesNeither speaker knows of routine tracer use in the First World War main guns asked about. A gun firing perhaps six shells per minute provides relatively few shots for observing a tracer and correcting fire. A tracer shell would also have a different flight path from the normal projectile, and selecting it would complicate loading. Machine guns make better use of tracer because their rate of fire is much higher. Foxo recalls tracer in some post-Second World War automatic 3-inch antiaircraft guns, while distinguishing those later weapons from the period in the question.