If you are adjusting the regulator down You need to remove the bottle then dry fire it until you hear the plenum bleeding down. Wait until the plenum gauge reads zero. Then you can adjust the reg down. Another way to get it to bleed the plenum is to adjust the reg screw counter clockwise slowly until you hear the plenum losing air. Again, wait until the plenum gauge reads zero before adjust ing the reg down.
If you are just dialing the Macro or Micro wheel, no just make sure the gun is not cocked.