Game Informer: The Arsenal of HALO 4

These are the details on the guns in HALO 4 (and a new gun) from the Game Informer article The Arsenal of Halo 4

ASSAULT RIFLE
DESIGNATION: MA5D Individual Combat Weapon System
MANUFACTURER: Misriah Armory
The MA5D ICWS is an exceptionally resilient gas-operated, magazine-fed, automatic rifle designed to execute close-quarters combat with lethal efficiency, regardless of hostile counter-op environmental conditions or duration of use in the field.

BATTLE RIFLE
DESIGNATION: BR85 Heavy-Barrel Service Rifle
MANUFACTURER: Misriah Armory
The BR85HB Service Rifle is a gas-operated, magazine-fed, semi-automatic rifle optimized for three-round burst firing, and proven to be an extraordinarily versatile weapon at a wide variety of ranges and in the hands of a capable marksman.

DMR
DESIGNATION: M395 Designated Marksman Rifle
MANUFACTURER: Misriah Armory
The M395 DMR is a gas-operated, magazine-fed, marksman rifle that maintains a smart-linked, telescopic, rail-mounted sight for scout personnel. This rifle favors mid-range to long-range combat, offering impressive stopping power.

SNIPER RIFLE
DESIGNATION: Sniper Rifle System 99-Series 5 Anti-Materiel
MANUFACTURER: Misriah Armory
The SRS99-S5 AM is a gas-operated, magazine-fed, semi-automatic sniper rifle with exceptional accuracy and the ability to simultaneously breach both energy-shielding and high-density armor, making immediate kills nearly effortless when this weapon is properly utilized.

RAILGUN
DESIGNATION: Asymmetric Recoilless Carbine-920
MANUFACTURER: Acheron Security
The ARC-920 Railgun is a compact-channel linear accelerator that fires a high-explosive round at incredible speed, delivering both kinetic and explosive force to both hard and soft targets alike.