I have used it for oracles and it does one shot them if you get them at spawn even on HM. However it just sucks using because it is a special weapon and dps'ing Atheon with a primary sucks (no Ghorn here) Usually I run IB or BH and there is no room for the foil because you can't really switch quickly after killing oracles. As for the rest of the game, the charge rate is so low that I prefer other fusion rifles like Light of the Abyss or my titans Purifier VII.