Keep those heavy tactical scopes, rings and bases locked solidly to the receiver by converting your rifle’s 6-48 mount screws to the stronger 8-40 screw size. Kit contains everything you need: 12 each of 8-40 x 1⁄4' and 3⁄8' Hex or Torx head screws, #19S and #28S drill bit, a taper tap and a bottom tap, plus one Fillister counterbore and our Screw Gizzie. SPECS: Screws are steel, blued. High speed steel drill bits, taps and counterbore. Refills sold per 12 pak.