Billet lower receivers are made from a solid block of aluminum rather than being forged, which is the traditional manufacturing process. A billet receiver is generally more expensive because it is more labor-intensive to manufacture.
The advantage of a billet receiver is that it can be machined more precisely than a forged one, which results in a higher degree of accuracy and fewer tolerance problems. This makes a billet receiver desirable for use in precision rifles or other applications where tight tolerances are critical.
Stephen Answered question August 28, 2022