Stapleton arrived outside the fort on 8 March with the French regulars, followed by Scott on 15th aboard "Serpent". The garrison began firing on the Jacobites as they constructed gun positions and one shot injured Grant, the engineer in charge at Fort Augustus. He was replaced by Mirabel de Gordon, whose performance at Stirling was regarded as so incompetent, some suspected he had been bribed. The besiegers opened fire on 20 March but poor roads and lack of horses to pull them meant the heavy guns remained at Inverness; the light guns and mortars available made minimal impression on the walls.