Overlap doesn't work for small and fast objects.

I tested it yesterday after work and I was able to get overlap events on 1 unreal unit thick collider when moving at 100,000 velocity. I think that translates to 1000m/s and that was without CCD.

So it’s a bit confusing why it doesn’t work for you. I would venture a guess that it has something to do with collision settings both on projectile and object you want to overlap.