Abstract: High pressure gas storage bottle with a single, small diameter filler neck aperture are charged with a powdered adsorbent such as activated carbon by drawing an evacuation air flow from the bottle receptacle at a point slightly below the filler neck. A charging fitting comprises a chambered body having an O-ring seal base which is clamped against the bottle nipple face by a compression nut. A length of rigid tubing having a tubular filter of pressed, microsphere tube walls at the distal or lower end thereof, descends through the body chamber and filler neck aperture. The tubular flow channel is connected to a vacuum source whereas the body chamber is connected to a powdered adsorbent supply conduit.