The Wheeler 89-Piece Professional Gunsmith Screwdriver Set covers the wide range of screws you find on rifles, pistols, shotguns and scope mounts. Its hollow-ground flat-blade bits have parallel sides that fill the screw slot and seat flat, instead of the wedge-shaped tip of a hardware-store screwdriver. A wedge tip rides up out of the slot under torque, which is how gun screws get burred and finishes get scratched. A hollow-ground tip spreads the force across the full slot depth, so you can break loose tight action screws and grip screws without chewing them up. Features: 89 pieces total 54 hollow-ground flat-blade bits in a range of widths and thicknesses 15 specialty gunsmith bits 8 hex (Allen), 4 Phillips and 3 Torx bits 2-1/4" shaft extension Hex-to-square drive adapter S2 tool-steel bits hardened to 56-58 HRC Custom-molded storage case Test-fit the bit in the screw slot before you turn it. The right bit should fill the slot side to side and bottom out without rocking.