Originally Posted by scrane
If flyers are dependent on fill pressure what could it be outside of the regulator?
That's the thing.....logic says it shouldn't happen. If it's something to do with fill pressure then the POI will be constant and move as the pressure drops.....the odd flyer doesn't fit that M.O.
I worked on a Steyr last year that had a POI shift related to cylinder pressure but it turned out to be the screw thread of the reg. As you screwed on the cylinder you could see that as it neared getting fully tight the cylinder was forced high into the chassis. I removed the reg and rotated it 180 degrees and hey presto problem solved. Never seen that before and none since......i suspect that at some time in the past the cylinder had come close to being cross threaded or the reg had been dropped or was a manufacturing blip as the 'neck' of the reg certainly wasn't true vertically.