If the weapon is loaded with standard ammunition, the weapon's firing will take the form of a spray of pellets, referred to as 'buckshot', which are quite powerful at close range but lose damage efficiency as the spray disperses and loses energy. As is typical of human firearms, in order to discharge the weapon, the trigger positioned at the top of the pistol grip must be depressed. The M90 shotgun is hefted like a rifle, with the user's dominant hand holding the primary pistol grip, and their off-hand supporting the weapon by holding onto the forend (the portion of the weapon which is acted upon by the user to facilitate the pump action, which also acts as a forward grip for the off-hand). A flashlight is integrated into the weapon’s forend, which also features a prominent reddish button. The magazine possesses a dull grey or glossy black finish with ribbed indents along its length. The magazine of the weapon is prominently positioned above the barrel, with the weapon’s glowing iron sights mounted atop it and the receiver located just behind, facing upwards, roughly in-line with the trigger. It is generally utilized alongside MAG 15P-00B rounds, and is designed as a more practical and cost-effective recreation of Misriah Armory’s M45E Tactical Shotgun, though in UNSC service it is considered to be functionally identical. The M90 is a pump-action shotgun, chambered in the extremely powerful 8-gauge magnum shell, and feeding from a 12-round, dual-tubular, non-detachable magazine.

Halo 1 shotgun