The Brownells #31 Solid Carbide Drill Bit is built for the demanding task of drilling into hardened steel parts often found in firearms work, including tough components like 03A3 receivers. Its single‑flute design cuts clean, accurate holes without chatter, crumbling, or work hardening, making it a trusted choice for precision gunsmithing. At 2 inches long, it offers the quill clearance needed when working with scope or sight‑mounting jigs, and when properly cared for, it resists binding and breakage. The solid‑carbide construction delivers exceptional durability, and its cutting geometry helps prevent work‑hardened surfaces that can lead to tap failure during threading. This bit is best reserved for hardened steels and situations where standard drills struggle, ensuring reliable performance in the most challenging materials.