A gag bar with a cam surface is used to reciprocate a kicker pin in a ram-driven punch assembly into the bore of a pierce nut in a pre-mounting position. The kicker pin and punch assembly are thereafter driven toward a workpiece to install the pierce nut in the workpiece and to fully separate a slug formed during the pierce nut entry from the workpiece. The gag bar and punch are thereafter reciprocated to allow the next pierce nut to be put in position.