Today I just successfully modify one streamline dart.

What I did is slightly different from youtube.

I cut and enlarged the little hole on the cap of the dart, instead of breaking the cap off. Then fill in with hot clue. Once the glue get cold, I use knife cut/shave off the overflowed glue and try my best to resume the shape of the cap.

Simple and easy, you won't feel a different in weight in hand, but you would feel pain if shoot your palm directly from a mod recon.

The accuracy of the dart increased shockingly A LOT.

EDIT: after mod, don't use this dart in nerf war anymore, not safe if shoot in eyes.