If you cycle the barrel of a minigun and there’s a round indexing, it could fire w/o the trigger applied. These things operate on a DC motor and would fire unless you cleared the feed tube when you cycled the barrel.
Loved the miniguns on our aircraft, they sounded like a chain saw, they could spray a football field with fire and kill anything larger than a rabbit in the field. When they operated, it looked like a solid stream of light (tracers) but there were five bullets between each tracer. (4,000 rpm)