Barrel nut assembly and method to attach a barrel to a firearm using such assembly

A barrel nut assembly for connecting a firearm barrel to a receiver of a gas operated rifle, said barrel nut assembly comprising:

• a barrel nut which is substantially cylindrical in shape and defines a longitudinally extending bore extending from a back end of said barrel nut along a longitudinal axis to a front end of the barrel nut, said bore having internal threads to be secured at the back end to an externally threaded front end part of the receiver, the front end of said bore being configured to receive a rear end portion of the firearm barrel therein, wherein said front end of the barrel nut has an integrally formed exterior flange having at least two squared off sections to render a forward face of the barrel nut substantially square, the at least two squared off sections configured to be captured within a fixture that rotationally restrains said barrel nut;
• and
• a locknut having external threads that engage with the internal threads in the barrel nut bore, enabling the locknut to be threadedly received within and connected to the barrel nut, said locknut being configured to compressively engage and secure said firearm barrel in position against said receiver as the locknut is screwed into the barrel nut and tightened to a preset torque value, a rotational orientation of said barrel nut about the barrel being independent of torque applied to the locknut.