A method for configuring precision rifle components and allowing users to change barrels when in the field comprising the steps of:
- providing a receiver subassembly with a receiver housing having a proximal open end and a distal open end connected by central lumen defining a plurality of substantially cylindrical contiguous cavities having selected inside diameters, said contiguous cavities being aligned along a central axis;
- wherein said receiver housing has a threaded outside diameter proximate said receiver housing distal end and said central lumen terminates distally in a first distal coupler-nut receiving cavity configured to receive a barrel coupler-nut and the first distal coupler-nut receiving cavity having a first larger inside diameter and threaded interior;
- and wherein said receiver housing central lumen has a second barrel extension receiving cavity configured to receive a barrel extension and the second barrel extension receiving cavity is coaxially aligned with and terminates distally in said first distal coupler-nut receiving cavity, wherein said second barrel extension receiving cavity has a second inside diameter which is smaller than an inside diameter of said first distal coupler-nut receiving cavity and, wherein said second barrel extension receiving cavity has a smooth cylindrical interior surface which terminates proximally in a transverse annular bearing surface;
- providing the barrel coupler-nut or retaining nut having a proximal centering force generating surface, and the barrel extension having a distal flange surface configured to bear on said barrel coupler-nut centering force generating surface;
- removing the barrel coupler-nut or retaining nut from the first distal coupler-nut receiving cavity and placing the retaining nut over a distal end of the barrel subassembly and slidably advancing the retaining nut to the rear to abut a flange of the barrel extension of the barrel subassembly;
- wherein said barrel subassembly defines a barrel bore having a bore central axis;
- holding or supporting barrel subassembly in a fixed orientation with an alignment slot of the barrel extension in a generally vertical orientation;
- sliding the receiver subassembly or module onto the barrel extension and rotating the receiver subassembly radially about the central axis so that an alignment pin of the receiver housing is received in and radially aligned by the alignment slot;
- automatically centering and coaxially aligning the barrel subassembly bore central axis with said receiver subassembly central axis by approximating said retaining nut proximal centering force generating surface with the barrel extension distal flange surface to bear on said barrel coupler-nut centering force generating surface;
- and
- inserting and threadably engaging and fastening the retaining nut with the threads in the central lumen to draw barrel subassembly into axial alignment with and proximally against the transverse bearing surface while automatically aligning the bore of the barrel assembly and central lumen of the receiver to be coaxially aligned with a common central axis.