Weapons are definitely [i]not[/i] aura-powered. Ruby is seen multiple times to load clips into Cresent Rose, and Yang loads ammo into Ember Cecila during the Yellow Trailer. Weiss' Myrtenaster is clearly shown to use a revolving chamber filled with various forms of dust. But enough about that.

Your understanding of dust ammunition, if I am reading this correctly, involves dust being filled into cartridges, like how our bullets are filled with powder, which is how I expect it to work as well.

Moving on to my weapons. Mr. Invincible too much? Try telling that to Nora's Magnhild, a giant warhammer / grenade launcher. Mr. Invincible simply has a pure defense / pure offense build, unlike Magnhild, both forms of deadly, deadly destruction. There's also, of course, Cresent Rose, a giant scythe / sniper rifle. Very deadly, especially in the hands of a skilled user, which Ruby is, of course.

Bloodseeker I don't see how it's unnecessary. It's a good weapons to use when you don't want to be lugging around a rocket launcher, plus there are only so many things you can do with a robotic arm, even in the Rwby universe, and I've already got enough functions in there as I possibly could, imo.