I'm reminded of a scene in Poul Anderson's
The High Crusade wherein an entire medieval town finds itself transported to a distant planet and at war with high-tech aliens...but they ultimately win the day, not for the least because they lobbed a live, armed nuclear weapon at an enemy stronghold. Fearing that the "humans" had invented a stealth nuclear attack system they quickly surrendered.
You see, they'd lobbed it with a trebuchet, and the shell wasn't air-dropped, nor fired via missile or artillery piece, nor was it brought to the target in any kind of trackable vehicle so...
