Close-in weapon system
A point-defense gun is a type of United Nations Space Command starship-mounted weapon. Like several other weapons in the UNSC's arsenal, the point-defense gun is designated as an "MLA autocannon". Though several models exist, the most common type of point-defense gun fires 50mm high-explosive projectiles.
 Design details
The point-defense gun functions much like the CIWS designs created during the 20th century, firing 50mm projectiles. Unlike Archer missiles and the MAC weapon systems mounted on capital ships, the point-defense guns are not used to engage Covenant capital ships, instead meant to intercept smaller threats like Seraph fighters or boarding craft to prevent (or at least lessen) the damage inflicted to a warship.
Because human operators lack the reflexive responses necessary to operate the point-defense guns to maximum effect, the autocannons are computer controlled and, if an AI is available, control is diverted to it. "smart" AIs seem better able to operate the point-defense guns than standard computers and also lesser "dumb" AIs.
 Operational history
Point-defense guns have been standard armament on UNSC vessels since the Insurrection, a common model being the AAA Helix gun. Later, Halcyon-class cruisers used a dual-barreled point-defense weapon system designated as the M910 PDN.
During the human occupation of Installation 04, the ODSTs that recaptured and secured the wreckage of the UNSC Pillar of Autumn from the Covenant managed to scavenge several of the ship's 50mm turrets. The ODSTs utilized the scavenged defense weapons and used them as anti-air defensive emplacements at Alpha Base.
A Halcyon-class cruiser defending itself from the Covenant boarding crafts using its point defense guns.
 List of appearances
- Halo 3
- Halo: Reach
- Halo: Combat Evolved Anniversary
- Halo: The Fall of Reach (First appearance)
- Halo: The Flood
- Halo: Evolutions - Essential Tales of the Halo Universe
- Halo Legends
- ^ a b Halo: The Flood, page 137
- ^ Halo: The Flood, page 215
- ^ Halo: The Fall of Reach, page 272
- ^ Data Drop 5