I was handling the DreamTac this morning and took a look at the pressure gauge on the front of the tube (sigh). No pressure. Checked the regulator pressure. 120 bar, as set. Okay. Pretty sure this means the leak is at the fill port or the front gauge. It's a bummer, but the gun is 3 years old and has operated flawlessly until now. Guess I'll fill it again tomorrow and see if I can determine the source of the leak. But maybe it's just time to tear her down, inspect and reseal. Now where did I put my replacement o-rings?