I guess there're ways to script it, although my attempts have been slightly unsuccessful
Not that hard actually, the only thing is that it may cause lag/FPS drop whenever large amounts of units firing at once..
Basicly what you do is you catch the bullet within the fired eventHandler, pass it into the script the eventHandler executes and then modify the velocity of the bullet..
There was an old script for OFP to do this but unfortunately the recent(ish) Great Crash wiped the attachment out of the thread it was discussed in..
If I happen to find it from me script collections I will 'ArmAtize' it and post it here..
(hence why I'm not moving this into the Addons board.. yet..
)