Abstract: Apparatus for x-ray viewing of the firing cycle of an air bag inflator includes a pressure tank for containing an inflator during a firing cycle thereof having an access opening in a wall for receiving the inflator. A mounting ring is secured in place in the access opening having a stop flange at an inner open end for engaging the base of the inflator when inserted into the open end of the housing and limiting the amount of insertion of the inflator into the tank. A pressure plug is removably securable in the mounting ring to engage the base of the inflator for rigidly securing the same in a fixed position in the tank and sealing off the tank during a firing cycle. An x-ray apparatus and film pack or recorder are disposed on opposite sides of the tank to view the progress of the ignition process during a firing cycle of the inflator.