Abstract: The invention includes a light-weight, high pressure cylinder, and a method of producing such a cylinder. The pressure cylinder uses a composite pressure barrel for maintaining and distributing fluid pressure therein. The composite barrel has tapered ends for retaining a pair of end caps. A split tapered collar having a taper matching that of the tapered end of the pressure barrel is provided to lock the end caps to the pressure barrel. The tapered collar has a threaded outer diameter for receiving the threaded end cap. The combination of the tapered collar and the tapered end of the pressure barrel provide a wedge when the end cap is threadedly engaged to the collar. By applying torque to the end cap, the two tapered surfaces are forced together and the end cap is locked to the composite barrel to maintain internal fluid pressure.