I'm a doctor, not a mechanic
Ammo for the UT Minigun (Minigun2) and the Enforcer. Both weapons take their ammo from the same supply, so with only a small amount of ammo it might be better to use the Enforcer since it does 17 points of damage while the Minigun only does 9-15 points. Each pickup gives 50 rounds with a maximum capacity of 199 rounds.
The subclass EClip only gives 20 rounds.