The weapon can be fired either by dropping the round down the tube (after aligning of the rifling bands) resulting in an automatic firing once the bomb hits the tube base, or by a controlled firing by dropping the bomb down the tube and pulling on a lanyard that will in turn set off the triggering mechanism in the base of the tube.
The weapon can be activated in two ways: by dropping the round into the tube (after aligning the rifling bands) to automatically fire upon impact with the tube base, or by manually firing it by dropping the bomb down the tube and pulling a lanyard that triggers the mechanism at the base of the tube.