A professional who tends machine that inserts and seats primers in center fire cartridge cases and shotgun shells. Responsibilities include:

• Starts machine and feeds cases onto pins of rotating dial plate or fills hopper.
• Observes flow of primers and cases through feed tracks to detect malfunction or jamming of inserting and seating punches and ejection mechanism.
• Stops machine to remove jammed primers or cases, using fingers, and notifies primer-inserting-machine adjuster of malfunction.
• Examines primed cases at ejection chute for defects, such as dents or scratches, and measures them for conformance to specifications, using fixed gauges.
• May tend machine that waterproofs cases.