Related Clues:

• Barrel filler
• Peas, for pea shooters
• Munitions, slangily
• Firing range rounds
• It's effective only when fired
• Magazine pieces?
• What some chambers hold
• Armory holdings
• Stuff in a barrel?
• GI's supply
• Balls of shot
• Bullets, say, in short
• One is going to get fired shortly
• Being the doctor, am able to be fired
• The doctor, that's me, so I may shortly get fired