Maho is correct. But you can achieve a simple and effective lazer beam effect by using flak. I used this method in Robolegs. Basically the flak/bullet model consists of two rectangular plains which sit perpendicular to each other. Then a beam/ray texture can be applied to each plain. And Voila! Obviously its not that simple coz the actual weapon needs the correct settings. Im on my mobile at the moment.
Hmmm... just had an idea. Later this week I will release a simple lazer rifle for the community to use as a base model.
Landman