Try this Orc. It's not optimized (loads the laser model everything shot hehe). I made a custom model for the beam. You can change the size of it in the CreateRG() function (X and Y axis) where it resizes the rg/mesh with ScaleMesh. (ScaleMesh rg\mesh,.7,.7,1)
http://webzoom.freewebs.com/zamagames/RailGun.zip
http://webzoom.freewebs.com/zamagames/RailGun.zip