Primers not seating all the way

Make sure you have the press handle set so that the full travel of the ram is achieved. The press handle must stop moving because of the stops in the linkage.

The primer is seated when the press handle is all the way up and the ram is all the way down. When the handle is all the way up the lower side of the shell plate carrier, where the primer pin is, should almost be touching the base of the press. If it is not either the handle is not in the full up position or the shell plate carrier was not secured properly to the ram and it has moved up on the ram. You would see a gap between the shoulder on the ram and the bottom of the carrier. The shell plate carrier is held in position by the black allen clamp screw on the front of the carrier. Refer to page 5 of your directions "Installing the Shell Plate Carrier" step four. Loosen the allen screw and make sure that the shell plate carrier is pushed all the way on the rams end and tighten the allen screw.

If that was the problem the primers should be fully seated if you make sure that the handle is in the full up position.