Abstract: Hollow cylindrical metal structures with internal contours are constructed from a thick-walled hollow cylinder of axial length, weight and outside diameter substantially equal to the axial length, weight and outside diameter of the desired preform. The cylinder is placed in a restraining cylindrical container having an inside diameter and length substantially equal to the outside diameter and length respectively of the cylindrical structure. The entire assembly is then rolled between a forming roll die having a contoured outside face abutting the inside face of the hollow cylinder and a support roll die abutting the outside face of the container until the inside face of the hollow cylinder conforms to the profile of the forming roll. Radial growth of the hollow cylinder during this contouring operation is inihibited by the cylindrical container. Axial growth of the hollow cylinder during the contouring operation is also inhibited with the help of flanges on the roll dies.