Buor joined the Navy as a Garde-Marine on 6 August 1756. He served on "Duc de Bourgogne" in 1756, on "Zéphyr" in 1757, and later on "Éveillé", on which he took part in the Battle of Quiberon Bay on 20 November 1759. In October 1764, he was promoted to Ensign and appointed to "Utile", in which he took part in the Larache expedition.