A lot of research on scheduling manufacturing systems with priority rules has been done. Most studies, however, concentrate on simplified scenarios considering only one type of resource, usually machines. In this study priority rules are applied to a more realistic scenario, in which machines and operators are dual-constrained and have a re-entrant process flow. Interdependencies of priority rules are analyzed by long-term simulation. Strength and weaknesses of various priority rule combinations are determined at different utilization levels. Further insights are gained by additionally solving static instances optimally by using a mixed integer linear program (MILP) of the production system and comparing the results with those of the priority rules.