We Know Our Onions
S6:E4
1973
IMDb
The platoon has gone to a camp to undergo an efficiency test. Meanwhile Walker has a van load of onions he's sold to Hodges, who isn't letting them out of his sight, thus he has pursued the platoon to the camp. Later, with no blank shells to use on the test, Mainwaring has a brainwave regarding what to use as ammunition!