Yes pakled that is the method to use for most realistic tracer action. Each round would be constrained to a slightly curving path originating at the gun barrel. Plane guns are set to converge at about 800 yards, so you would have to take that into account too. Here is a simpler method to use for near instant tracer gratification. It is not nearly as realistic though. I will post on the other method later after I have had time to experiment.