And slap normal effects on them. They aren't beams right now, they are just normal guns without a projectile effect and with a beam as a (muzzle) flash effect. Unless you slap like 100'000 ms speed or such on them, they will always be just a projectile which doesn't hit where the beam points. And even then the projectiles can be fire in a greater angle than the turret model itself can turn in some cases* (or at least that's the case for fighter guns, try firing to the sides for example, the gun turns maybe 90° in total, but the shots can be fired almost in a 120° radius...).
EDIT:
Most important is, turning off the "force_gun_ori" though, which makes the weapon fire no matter if it is aimed or not.
You practically could teamkill all around you with it, trying to hit someone. I mean sure, the hit chance of it is low enough on enemies already, but you never know.
EDIT0: To clarify:
The flash is fixed on the turret model, it moves with the turret (and with the ship, as the turret moves with the ship) and the projectile (proj effect or constant effect) moves only with itself (and the ship it hits, once it hits, I think). The impact effect moves with whatever the projectile hits.
EDIT1:
The problem of a beam weapon is, that once the projectile hits the projectile effect disappears. So, you can't just make a beam by using a long spear-like projectile. Also, again, the speed would need to be extremly high...which then again causes the beam to disappear immediatly. (Hm...can't you make an effect with a "infinite" trail? Probably too much graphics lag ...)
Hm. I am no Dev, but this sounds worth trying. The guns are impossible to use as a player and only NPCs are able to use them correctly. So in theory they should work, but not for players. If Syrus' changes make them more useful, please try it.
I am no developer and i dont understand anything about it either, but i show my support to fixing those weapons too.
Of course, there are some stuff that are more important right now, but if what the topic creator proposed could be tried would be nice, would be very cool to have some "real" beam weapons in disco.