The raid drops plenty of ammo. If you're running out of ammo, it means your movement is all wrong in fight encounters. If your properly cycling weapons and popping shields and priorotising different targets at different times you shouldnt ever have a problem. Like final boss fight, mele dogs as you run around to refill your kinetic, pop higher ranks for energy, then majors for your heavy. You see guys using their energy weapon for everything, popping shields then carrying on spraying and running low. Then the next major arrives and you cant break its shield. Its sensless. You element a shield off, then spray them down with your kinetic. You team shot majors to save even more ammo. Theres tons of ways to deal with ammo management, you just have to play smarter