Some folks have problems with the Auto Disk just for this reason--the disk does not make a complete cycle. Not only must the chain be taut on the Load Master but the powder-through expander die MUST be set low enough to cause the disk to move completely out over the drop hole in the measure.
People seem to get into this because they don't want to bell the case mouth too much thinking that will 'work' the brass too much and shorten case life. That may be, but a short charge, or no charge, is much the worse thing.
I always check at the start of every loading session to make certain that the disk cycles completely.
Setting the chain for a Load Master is very simple--if you haven't seen it, watch this video series--it also tells how to correctly set priming, dies, etc.
*-Setting up a Load Master Part 1.
http://www.youtube.com/watch?v=tFprUSI7WuM
*-Setting up a Load Master Part 2.
http://www.youtube.com/watch?v=aCnWhkJSUQs