Do gun trials come before turret trials?

Are naval guns normally tested in open mounts before turrets are proved?

Usually yes: gun testing precedes a separate turret-testing programme, although installed turrets can later support continuing barrel trials.

Barrels are usually tested mainly in open mounts at first. Turret trials follow as a separate programme, and some mountings are proved before installation aboard ships. Turrets can subsequently remain at shore firing ranges for testing later gun barrels and production batches.