The Golden Gun is a rare example of the prestigious artillery of the 17th century. The restoration of the gun barrel became necessary in view of the condition of the object and the loss of the handle and the breech head of the central muzzle. Since only scarce details were known about the structure of the gun tube, complicated technological investigations had to be undertaken. At the same time, investigation methods could be carried out by uncomplicated means at the restoration workshop. The composition of the patina in the bore and chamber and a possibility for its preservation, of the reconstruction of the handles and the breech head of the central muzzle and their fastening to the original, are described. The gun tube contains copper, leather, iron, hemp, and wood.