No prob. Yeah, you’ll eventually hit a threshold where stuff just can’t render fast enough to display properly. It’s the same with using meshes for sword swipes; you’ll get to a speed where you’re panning the texture too fast on the mesh for Unreal to keep up, and it starts to visibly artifact.
I can’t remember off the top of my head, but there’s a setup to use with the beam method so it pans and tiles the same amount regardless of how long the beam is. That keeps your bullet from stretching and speeding up if you shoot something far away or really close, so there’s no noticeable difference in the tracer regardless of what you’re shooting at