From Halopedia, the Halo wiki
Infantry support weapons are a class of crew served, man-portable, specialized weapon systems. By design, they require an "assistant" crew of more than one individual to function at optimum efficiency due to its operational complexity, such as requiring one person to load while another fires, or another person to carry a bipod and additional ammunition. The weight and bulk of the weapon system often also necessitates multiple personnel for transportation.
When used by individuals, these weapons are much larger than the standard shoulder-fired military service weapons, and require two hands to heft. As a consequence of their weight and bulk, players move more slowly while carrying them, and cannot duel-wield, throw grenades or make melee attacks while wielding the weapons; this increases vulnerability to enemy grenades, snipers, and vehicles, since the reduced mobility decreases ability to make evasive maneuvers.
While originally designed to be fired from stationary mounts, these weapons can be removed from their mountings or tripods and carried as man-portable heavy weapons. Effectiveness is reduced, however, by a number of factors; while mounted, the benefit of feeds from ammunition stores present in the mounts provide effectively unlimited ammo, but once removed and carried, the ammo loaded in the weapon is limited. Furthermore, accuracy and stability is typically diminished when fired while handheld, compared to firing the weapon from its mount.
List of infantry support weapons
List of appearances