What must be adjusted before sizing the first case to prevent the decapping pin retainer from bottoming out?

To prevent the decapping pin retainer from bottoming out before sizing the first case, it is essential to adjust the depth of the decapping pin's travel. When resizing cases, the decapping pin must have adequate clearance to push out the spent primer without hitting the bottom of the sizing die or the shell holder. Adjusting the decapping pin's travel ensures that it can move sufficiently to decap the primer while preventing damage to the die and maintaining proper function.

If the travel of the decapping pin is not adjusted correctly, it may lead to unnecessary stress on the pin and retainer, potentially causing breakage or malfunction during the reloading process. Ensuring proper pin depth allows for efficient operation and prolongs the lifespan of the reloading equipment.