Abstract: A chamber reinforcement for composite firearm barrel and method for forming the same. In one embodiment, the barrel includes an inner tube defining a bore that provides a bullet path and an outer sleeve preferably made of a material lighter in weight than the tube. In some embodiments, the inner tube is made of a material that preferably has a greater density and strength than the outer sleeve. The reinforcement in one embodiment may be in the form of an end cap disposed on a portion of the sleeve. The reinforcement preferably is made of a material comparable to the inner tube in density and strength to reinforce the area where a chamber is formed for receiving a cartridge. In the preferred fabrication, the reinforcement, tube, and sleeve are forged together to provide a strong and unitary structure for withstanding combustion pressures and forces associated with discharging the firearm.