Assault Rifle Ammo Case is an item that can be found in Resident Evil: Revelations 2.
This item enable the player to carry more assault rifle ammunition.
This ammo case can be found inside the sewer corridor where the player fought the Vulcanblubber. As Claire, the player can jump from the top of the stairs to the hanging platform and to the other side of the seal gate, turn the valve to open it. Switch to Moira, go through the open gate and crawl up the dried up pipe to find the chest.