The GAU-3/A is the primary weapon of the XS1 Goliath scorestreak. It has unlimited ammo, but can overheat from prolonged fire. It has a slow rate of fire and poor accuracy, but inflicts high damage on impact, as well as small amounts of splash damage.
The GAU-3/A also appears on the XS1 Goliath in Exo Survival, where it is used by enemy ASTs and can be used by the player if they spawn an XS1 Goliath. The version on the XS1 Goliaths used by the player act relatively the same as in multiplayer.
The GAU-3/A appears on the XS1 Goliath in the Exo Zombies maps Carrier and Descent. In Carrier, it is used by enemy XS1 Goliaths that spawn during rounds with Gas Bombs. In Descent, XS1 Goliaths can be found in Orbital Care Packages, and come with the GAU-3/A equipped on them. It acts pretty much the same as in other game modes. If the player collects an Open Fire power-up, the GAU-3/A will not overheat during the duration of the power-up being active. If the player buys the Exo Soldier Exo Upgrade, the player will be able to fire the GAU-3/A while sprinting in the XS1 Goliath.