Abstract: A drop bar firing system is provided with a drop bar retracting means that insures that the lower end of the drop bar cannot come into contact with the firing head after a misfire, as the drop bar is fished or the tubing string removed. A safe arm mechanism requires the pressure in the well as the perforating gun is lowered into the well to arm the tubing conveyed perforating firing means. A safe position is automatically developed by the safe arm as the perforating gun is brought out of the well if a live gun must be retrieved. A specially shaped device to fire the tubing conveyed perforating detonator includes a probe of small diameter requiring a heavy impact on center.