Sending the object forward base on camera and mouse

I’m having a little problem sending my object to where my mouse is and where I am in the world. Not sure what math to call to get it to go in the right direction.

            self.bullets[self.NumberOfBullits] = loader.loadModel("towns/bullit") 
            self.bullets[self.NumberOfBullits].setPos(base.camera.getPos())
            self.bullets[self.NumberOfBullits].setScale(.0005,.01,.0005)
            self.bullets[self.NumberOfBullits].reparentTo(render)
            self.mpos=base.mouseWatcherNode.getMouse()
            self.bullets[self.NumberOfBullits].posInterval(.543,Point3(float(base.camera.getP()),float(self.mpos.getX()+10),float(self.mpos.getY())),fluid=1).start()

Look at the picking tutorial. It uses collisions from the mouse to figure out where the mouse ray hits.