440mm Heavy Artillery

A 440mm, or "four-forty" as referred to by UNSC troops, is a UNSC heavy artillery weapon developed around 2552.Halo: Ghosts of Onyx, page 116 It is one of the largest caliber UNSC weapons.
==History==
During a training mission on Onyx, one of the Spartan-III candidates mistook an explosion caused by an Onyx Sentinel for a 440mm piece.
==Appearances==
*Halo: Ghosts of Onyx 
==Sources==
Category:Human Weapons
Category:Halo: Ghosts of Onyx