US-10228209-B2

A method of making a continuous fiber barrel wrap sheath onto a steel riffled barrel liner of a gas-operated firearm is described. A wrap made up of composite fiber is wrapped onto a steel riffled barrel liner in a continuous fashion, with no interruption within the steel liner for the purpose of delivering high pressure gas through the steel liner. After joining the composite wrap to the steel barrel liner, either by mechanical or chemical procedure, a slot is formed by carving out a top and/or a bottom of the composite. A gas key insert is then placed in the made slots and retained by mechanical or chemical procedure. Finally, a gas port is drilled through the key insert.