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

A fixture configured to rotationally restrain a barrel nut of a gas operated firearm comprising:

• two halves each comprising a top surface, a bottom surface, an inner surface, an external surface, a front surface, and a rear surface, wherein said two halves are pivotally secured to each other with pivot rods about said top surfaces of said two halves;
• two primary inserts provided within said inner surfaces of said two halves about said front surfaces of said two halves, wherein each of said two primary inserts define a forward face, an interior portion, and a cutout provided on said forward face, wherein said cutout is configured to receive and rotationally restrain said barrel nut during assembly of said gas operated firearm, wherein said interior portion is configured to conform to an exterior profile of said barrel nut, said exterior profile of said barrel nut defined by a surface structure extending between an area behind a flange adjacent to a front end of said barrel nut and a rear end of said barrel nut;
• and
• two secondary inserts provided within said inner surfaces of said two halves about said rear surfaces of said two halves, and adjacent to said two primary inserts, wherein each of said two secondary inserts define an inner portion configured to conform to an exterior profile of an upper receiver of the gas operated firearm.