If you look down on the adjusting ring from directly above, you will see that the front edge is cut at a slant.
Directly under this is the gas vent, which can be seen if the ring is turned all the way to the right
The amount of gas impinging on the piston depends on how much of this vent is exposed.
From what you say, you have the vent fully closed, which is why the brass is heading into the next county.
What you need to do to set it correctly is turn the ring to the right a click at a time until the case fails to eject or feed the next round & then turn it back two clicks.
The brass should then go 6-12 feet, depending on the state of the recoil spring & how tight the action is.
Most FAL's with standard length barrels will operate correctly with the adjustment ring about halfway between fully open & fully closed.
If the rifle fails to feed even though the brass is being thrown a long way, then the recoil spring could be weak, or the spring & recoil tube covered in grease & dirt - it only needs a light coat of oil.
If you suspect the spring, then get a buttstock removal tool to remove/replace it, or it WILL shoot out of the butt & hit you or something you really don't want a greasy pattern on.......