Quote Originally Posted by Robert_Lavin View Post
Hadn't thought about that.

I trying to understand why a failed regulator gives the low-high-low power change from a full fill like an unregulated gun.

I suppose I need to understand why the unregulated power curve is as it is.
Because the reg has failed, it's no longer in the equation, so the gun will run as unregged in its characteristics. The curve comes from the influence of the springs (hammer, valve return) which are a fairly repeatable pressure. The bottle is in a constant pressure decline shot by shot. The bottle pressure pushes back against the valve as a return pressure. The hammer and spring assembly works against this to knock the valve open. Because the pressure from the bottle is slowly declining, the hammer knock open has slight more eefect on knocking open the valve as the resistant pressure in the bottle drops (more dwell time in the open position) so power rises. However, once the peak of the bottle pressure/dwell/power is achieved, the pressure in the bottle will continue to fall and the dwell time is of no consequence as the bottle pressure cannot realistically achieve the power it did at higher pressure. That is the downward arc of the curve.

A reg, if it's working correctly, will draw from the reservoir (bottle) and create a second chamber of regulated air at a fixed pressure. You then have a fixed spring pressure setup working against a constant pressure.. ... This is the consistency a reg achieves. Until the bottle pressure drops below the reg setting and then you're "off reg" and the inconsistency returns.
If your reg is set correct, there should be no "spike" in power as you come off reg.