I was reading another question and started to wonder what the dimensions of a blaster bolt are.

Usually in universe when we see a bolt fired it appears as a cynlinder with some length L.

Take this bolt for example: (imagine it's being fired parallel to your screen, so you are looking at it from the side):

Is the length of this ex. the actual length or just the apparent length due to the fact it is travelling at the speed of light?

If this is not it's actual length but the apparent length due to relativity, would a laser bolt actually just be a sphere?