I used a long #40 to drill the first mounting hole through the supertrack and sub structure. Stepped up hole to full size for screw and then opened top of track to allow a countersink to pass through and countersink lower part of track. Inserted screw with nut to hold in place. Used long #40 to drill aft mounting screw location in "trigger guard". Removed track and drilled aft hole to full size from bottom. Upsized hole in aircraft. Match drilled the shims for forward and aft. Repeated process for left side track.
