Forrest68,
Just give it a shot. When my case sensor wasn't tripping the primer arm to come down, loosening the screw worked for me.
The "case sensor" is the piece that pulls on the spring that releases the primer arm which lets it drop allowing another primer to advance. Right now your problem is that the case sensor isn't moving enough to activate the spring, or the spring wasn't installed correctly. Assuming that the spring is installed correctly the logical conclusion is that the case sensor isn't moving enough to actuate it.
If it isn't moving enough to move the spring out of the way then it is binding on something. If you are utterly convinced that the "sleeve" is keeping the screw from binding on the case sensor by all means ignore my advice, which was free and cost you nothing anyways.
Jimro