If your cases are tipping or failing to insert into the shell plate, check to make sure the riser is installed on the slider block if required. See Six Pack Pro instructions grid on page 8, column "Univ. Case Feed Slider Block" column of the instructions.
If the cartridge you are reloading requires the riser, slide the riser block on top of the case slider block until the front and back are flush. Tighten Phillips screw on riser block.
Picture below showing case slider block with riser installed.
