Because it only will go through c_move once now, you need to put it in a while loop while (me) {}. When the bullet is removed, 'me' will return false and the while loop will automaticly stop to prevent empty pointer errors.

EDIT: And you need to replace the first nullvector with vector (speed, 0, 0)
EDIT2: Ánd if your game is not multiplayer, you can just use ent_create isntead of ent_createlocal