Possible Clues:

• With these types of vacancies to fill, firing them will achieve nothing
• Shuts out, in baseball
• Cartridges with explosive charge but no bullet
• False fire?
• Pointless tiles?
• Stockpiles containing fifty empty cartridges
• Ersatz bullets
• You'll never get shot by the pound in places of money
• You'll never get shot of them
• They may be loaded