US Patent 7810271 Modular rifle systems and methods

In embodiments, a modular rifle includes a lower receiver assembly, an upper receiver, and a coupling mechanism. The lower receiver assembly that can be separated into a lower receiver portion and a magazine well portion. The coupling mechanism is configured to releasably couple the portions of the lower receiver assembly together. The coupling mechanism including an aperture and a pin that can be moved into and out of the aperture. The upper receiver is releasably coupled to the lower receiver assembly.