Possible Clues:

• Heavy firepower, ominous positioned in middle of major road
• Holding line, it rarely disturbed gunners
• Launched weapons
• “When political ammunition runs low, inevitably the rusty ____ of abuse is wheeled into action” (Adlai Stevenson)
• Shots fired from vessel, not well protected
• Battery is run down in motorway
• Large weaponry
• Weapons poorly positioned in vessel carrying vital supply
• Battery ailing in vessel
• Big guns ditching organisation's leader -- possibly worse coming in