The charging handle is an inconspicuous rounded-off protrusion on the left of the weapon's body, and the ejection port is situated on the right. The magazine which feeds the rifle is inserted behind the thumbhole pistol grip in a bullpup configuration, another trait typical of the ICWS series. While most MA5 ICWS rifles feature this to some extent, it is most prominent on the MA5B. The most characteristic part of the MA5B's architecture is the accentuated shroud situated atop the barrel, which houses the weapon's integrated computer and display. Early in the Covenant War, SPARTAN-IIs also frequently employed MA5Bs with underslung M301 40mm launchers to fire HE grenades, notably during Operation: SILENT STORM and the salvage operation on Netherop. Its barrel can be adapted for use with suppressors to combat the conspicuous report of the weapon's firing, making it especially suitable for stealth fighting SPARTAN-IIs made use of this attribute during the Battle of Sigma Octanus IV. One significant aspect of the MA5B's design is its capacity for modification.

The weapon's automatic rate of fire is 15 rounds per second, but it can be limited to semi-automatic or 3-round burst via a fire selector to conserve ammunition and alter firing pattern. Hollow-point rounds are loaded into magazines marked with red paint for rapid identification. MA5Bs typically feed from 60-round detachable box magazines. The MA5B is a gas-operated automatic rifle chambered in the widespread 7.62x51mm cartridge, most often used with standard M118 FMJ-AP ammunition, though also employed with shredder and hollow-point rounds.

System shock wiki assault rifle