Huge cannon, which fires slow moving plasma-charged projectiles. Rounds are highly effective versus armor, and obliterate what is left underneath.
A feared weapon platform, rarely deployed due to the complexity involved in manufacturing a built-up barrel that can safely fire 510mm high-explosive shaped charge rounds. When such a shell impacts a target, the Neumann effect causes the warhead to propel a jet of molten metal into the target's armor, vaporizing a small area, causing hull breaches, depressurization and extensive internal damage from the spall.
The Hellbore Cannon is a large ballistic weapon firing high explosive shells. It has the lowest OP cost of any heavy weapon in the game and is generally unmatched in the anti-armor role against large targets. At the same time, the slow turret turn rate, rate of fire and projectile velocity leave it ineffective against smaller targets.