Okay! So with that last bit, that’s great but not what we were asking about in the first post. 
No worries though!
You need to go to your projectile Blueprint, and select each component that has collision, and set that collision to “Ignore All”.
Again, this won’t solve the problem, but we’re trying to find the cause then go from there! But if you’re doing something this simple here, the problem is likely on the Projectile.
Another thing you can do is put a printstring anywhere in this to prove that the event is going off in the first place!