gun chamber—
1. the part of a gun that receives the loaded charge:
- According to Massalamani his own gun chamber got jammed, so he could not shoot.
2. an apartment on a warship used by the midshipmen and junior officers:
- He lost the advantage that the suddenness of his irruption into the gun chamber had given him.
gun room— = gun chamber 2:
- John was popular but found the discipline of a fighting ship difficult…. He was often called up to join his senior officers in the gun-room.