Wheeler Engineering 43-Piece Professional Gunsmithing Screwdriver SetThe Wheeler Engineering 43 Piece Professional Gunsmithing Screwdriver Set features the most popular bits for gunsmithing. As any gunsmith will tell you, screwdrivers are the most important and most used tool on their bench. These bits are made from S2 tool steel and hardened to 56 58 Rockwell "C". Also featured on these bits is the Hollow Ground design which has a gentle curve as it reaches the tip of the bit instead of being straight throughout the