A Rogue-class starfighter with a proton cannon attached
During the Clone Wars, both the Galactic Republic and the Confederacy of Independent Systems utilized proton cannons as a form of powerful artillery.
Proton cannons were a type of weapon that delivered significant energy-based firepower. The Separatist's J-1 proton cannon served as one example; it was a droid-operated anti-aircraft cannon. A small number of these cannons possessed the ability to destroy an Acclamator-class assault ship. Proton cannons could also be mounted on smaller vehicles, such as the Rogue-class starfighters.
A group of Pakiphantos equipped their Z-95 Headhunters with proton cannons. Despite the Headhunters being relatively small, their proton cannons were powerful enough to penetrate the enhanced armor plating of larger, capital-class ships like the Millennium Falcon.