A modular precision rifle assembly 150 and a method for configuring rifle components allowing users to change barrel subassemblies 214 (i.e., for a replacement barrel for use with the same ammunition or a barrel configured for shooting a different ammunition caliber or type) includes three main components including a receiver subassembly 212, a barrel subassembly 214 and a forend subassembly 200. The receiver subassembly 212 includes a receiver housing 300 with a central lumen defining a plurality of substantially cylindrical contiguous cavities aligned along a central axis 300CA. The barrel assembly's bore is automatically forced into axial alignment with central axis 300CA when a user tightens a barrel coupler nut 500 against a barrel extension 400 due to the centering force generated when the extension's centering surface 410 bears against the coupler nut's cooperating centering surface 520.