Armory

''Were you looking for the Halo 2 level, The Armory, or the Field Armory?

An Armory is a military depot used for the storage of weapons and ammunition and are quite common on UNSC ships and bases.

Pillar of Autumn
Halcyon-class Cruisers are known to have at least two armories; one near the Bridge and a larger one near Engineering. However, since the Autumn was heavily modified, it is unknown if standard Halcyon Cruisers are exactly the same as it.

Among the weapons that were noticeably absent from the Autumn's armory were Sniper Rifles and pistols. Another kind of weapon that didn't appear there at all were Frag Grenades. However, many Shotguns, Assault Rifles, Rocket Launchers and ammunition for these weapons were still in their racks, though some weapons were scattered everywhere with no ammunition in them at all.

Cairo Station
Large orbital space station like these are fitted as well with at least one armory, in case of enemy boarding actions. Only one is seen onboard Cairo Station in the level with the same name. It contained a large amount of weapons, including Shotguns, Battle Rifles, SMGs, and ammo. It also housed the Shield tester used to bring John's armor shields back online.

Crow's Nest
A 20th century base refitted for UNSC usage against Covenant invaders near Voi, Kenya. No official armory is seen inside this base, however lots of weapons are found scattered throughout the level, mainly held in racks.

Trivia

 * Armories can hold many different UNSC weapons, such as Shotguns or Assault Rifles. They serve as good weapon and ammunition storage in time of need.
 * During the crucial events of the Battle of Installation 04, the Pillar of Autumn's armories were almost completely emptied of their weaponry during a raid on the crashed ship by UNSC forces. The retrieved weapons were taken by Pelicans to Alpha Base and distributed to the personnel. During his mission on board the Autumn, John-117 rearms in the one next to Engineering to battle the Flood and the Covenant to collapse the ship's reactor core and destroy the ring.