If the pump stays at 50 when the pump is off, the gauge is stuck. If it jumps to 60 when running, the backpressure control is set to 60 psi. That may be too high. And if you run out of water, the backpressure would have to drop as well. I wonder if the gauge hole is as plugged up as Rancher thinks your pressure switch tubing is? That would explain the gauge not moving much.
You can't draw down a well with a jet in it. The column of water under the jet is always under vacuum and the well will give only what it can, regardless of what the pump wants.
One other thing. The air control and the copper tubing are practically useless with a deep well jet pump. The air control needs vacuum to operate and with a deep well jet pump with the backpressure control set properly will only have vacuum for a split second when the pump starts. This is not enough time for the air control to fill with air.
bob...