Related Clues:

• It's effective only when fired
• What some chambers hold
• Armory holdings
• Stuff in a barrel?
• GI's supply
• 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
• I'm the doctor, but may be fired shortly
• Although I'm the doctor, may be fired
• BBs, for example
• Gun-shop stock
• It might be in a belt
• Bullets, informally