FPS Drops on Lucian's Lightslinger procs

I just played a game as Lucian to check out how well he would do after the nerf. Turns out it was a tad worse than I thought. Every time I would proc Lightslinger, my FPS would drop from it's capped 80 fps to around 30. It was noticeable enough that most times the screen would stutter to the point of not showing the first auto-attack. I don't think it's related to my computer since I've never had this problem before and that visual-intensive teamfights with other champs are just fine. Idk what would cause this problem though.