A method and apparatus for hydraulically forming metallic tubular bodies are disclosed. A forming die is provided, with the interior of the die configured to receive the tubular body to be shaped. The tubular body is filled with liquid, preferably water, with the interior of the tubular body then sealed. A forming plunger is thereafter inserted into the tubular body whereby localized hydraulic pressurization of the liquid within the body is effected. Outward deformation of the body toward the interior of the forming die thus results, with the formation of tapers, steps, projections, or other desired features readily achieved. The present invention is particularly suited for forming the tubular components of musical instruments.