Ammo Drum works on rifle-type, sniper-type, and bow-type primary weapons. The Grakata, while a rifle, has a unique maximum ammo capacity of 750. In Actualización 14.2, maximum ammo for heavy weapons was changed to 20 (the exception being the Torid, which has a max of 60), and the maximum ammo capacity of the Rifle de flujo was increased to 600. Ammo Drum is only useful on weapons with poor ammunition efficiency.
The following table shows the additional ammo capacity granted by Ammo Drum: