I recently got a LNIB Empire Axe, and the first day I played with it the gauge on the regulator kept creeping up to around 250 psi from the 180 psi I set it to. This only happens in between shots when the gun is idle. Once I shoot, it goes back down to 180. I don't think the pressure is actually moving, as each shot seems to be the same velocity. I'll have to test it at the chrono next time I play.
On a side note, the gun seems to be almost new in box from Trademygun.com, as it is one of those stormtrooper white Axes that had the coating issue (which mine doesn't seem to exhibit). Toolbox and barrel sock weren't even open. Should this go away as the gun gets broken in, or should I do something to remedy it?