Board Thread:Off Topic/@comment-27144409-20181126150808/@comment-26397825-20190308083213

I don't think we've actually seen it be applied to blades except as an effect that is held just in front of the weapon (Weiss's shield vs the WF Lieutenent) or send forward similar to an aura slash (Weiss's fire slash in the seocnd Weiss Short). Raven and Adam's blades are forged with the Dust during the creation process, making them blades made of Dust rather than blades that have the Dust effect added later.

To me it sounds more like they'd be wasting a bullet to do a Dust effect that sorta surrounds the bullet but doesn't actually give the bullet elemental properties. However, having a removable cartridge filled with various dust that the selector then chooses makes sense from a reloading point of view; Weiss has to reload each vial individually after all. And then you can do things like insert a pure Fire cartridge for when you only want Fire and don't want to have to fiddle with the dial - no matter which colour it's on it's always going to pull Fire Dust.