To all who are still interested.
I have been playing around with my M930 to try and shed some light on this. First of all ghost loading is not easy. Maybe with practice it gets better but I’m not good at it.
With no shells in the gun I can’t seem to see how ghost loading works. I open and close the bolt and it does not seem to be possible.
When I ghost load the gun it works. My hypothesis is that the mechanical systems in the gun work differently when load vs unloaded. This makes sense because when unloaded you pull the charging handle to the rear the bolt locks back. When loaded the bolt does not lock back until you’ve fired the last shot. I think this is key.
I ghost loaded the shotgun with 3 rounds.
This pic is showing the ghost load positioning. The bolt is closed and there is a shell in the pipe (note the safety is on). There is a shell on the elevator and a shell in the tube. You can see that the shell stop is in the “closed” position.
I then pull the charging handle slowly to the rear and as I extract and eject the shell in the pipe the shell stop remains closed.
Once the shell ejects the lifter immediately lifts and the shell stops remains closed. This is the step that does not jive with an unloaded gun.
Once the shell is ejected the bolt comes forward to chamber the ghost load (pic above). While this is going on the shell stop remains closed.
Once the bolt is closed the lifter drops and the shell stop is opened momentarily to push a new shell onto the lifter. This cycle repeats itself until the tube is empty.
I don’t have the full story but it works. There is something in the mechanism when the gun is loaded that times the shell stop to only “open” when the lifter is down and the bolt is closed or almost closed.
Maybe others can chime in on the specific parts of the system that work together to make this happen.
At the end of the day it’s a neat range trick for competition shooters but not really of value to me.