Abstract: A pressure vessel having a relief area onto which a flange of a side port can be attached. The relief area includes a planar mating surface raised from the cylindrical sidewall of the vessel. A method for forming the pressure vessel includes providing a cylindrical mandrel provided with a side port spacer. Fiberglass is wrapped onto the mandrel and space. The fiberglass is impregnated with resin and the resin is cured. A metallic insert ring is embedded in a full bore open end of the pressure vessel. The ring has a cross-section having a height to width ratio of less than 0.7.