UNDER OHIO REVISED CODE, a person can be charged with aggravated robbery if they have done one of the following acts while fleeing from, committing or attempting to commit any theft offense: Having a deadly weapon on them or under their control, and displaying the weapon or indicating they have the weapon, or using the weapon; inflicting, attempting or threatening to inflict serious physical harm on another person; having a dangerous ordnance (mounted guns; artillery) on them or under their control.
So...it could have been a dangerous ordnance.