Here ya go buddy...try it like this...
1.) Open your map in Chunk adder, and add a trigger to the carbine.
May sure you put the stuff I highlighted the same...
2.)Open your map in Dothalo, and goto the carbine.weap
For the dependencies, make them look like this...
In the tag editor, go to firing type, then goto chunk 0, under button used, put R, and under projectile used, Choose second.
For chunk 1, under button used, put L, and under projectile, put one.
Under flags, select disable grenades.
Now your done with the weapon stuff for now.
Goto the beam_rifle_beam.proj, and null out everything but the contrails, and swap the contrails for the needler contrial.
Then, goto the needler contrial, then it's bitmap, and inject a solid red image...
Now you are done with Dothalo.
Open your map in H2x, and goto the carbine.weap, then hit meta editor. Goto the firing type tab, and for projectile 0, make everything zero, for projectile 1, make it identical to the Battle Rifle. Then goto the projectile tab, for chunk 0, make everything look like this...
And for chunk 1, make it match the BR.
Resign your map, and you should have a BR with a laser sight like so...

Formerly known as Limpmybizket.