This addon makes all bullets shot from guns to have a coloured laser beam from the gun to the point the bullet hit.

The trails are coloured by team. Terrorists have red beams whereas Counter-Terrorists have blue beams. (should work in other games also, tested only in CS:S)

The config block at the start of the script file has two variables you can alter to make the script better suit you. You can change the sprite model used for the tracers (defaults to laser.vmt) and the time the tracers are visible (defaults to 2.0 seconds, set to 0 for permanent).