Yes, you can change the velocity of projectiles in Battlefield 2. You can give a projectile zero velocity or even give it negative values and make the projectile travel in reverse. I've actually been testing differant velocity speeds of the lasers for the last few days.

I was playing around with laser effects yesterday.. It is actually quite an interesting area, since you have to consider very different kind of aspects than with ordinary bullets. Here´s couple of sreenshots of what I have done so far..