In Moscow, he engaged in Vakhtang's cultural and educational enterprises. Following the king's death in 1737, his nobles, including Guramishvili, pledged their loyalty to the Russian crown and joined the Imperial army, forming a Georgian Hussar Regiment. On this occasion, Guramishvili was bestowed with estates at Myrhorod and Zubovka in Ukraine. As a Russian Hussar officer, he fought in the wars against Ottoman Empire (1735-1739), Sweden (1741-1743) and in the Seven Years' War (1756–1763) during which he was wounded and captured by the Prussian army. It was not until December 1759 that he was released from the Magdeburg prison and allowed to return to Russia. Invalidated, Guramishvili retired from the military service and withdrew into his estate where he lived together with his young wife Princess Tatiana Avalishvili.