When creating a bullet, place it at the click point and rotate it towards its source point. Then move it to (set its location at) the source point and turn it 180 degrees.

Could you maybe give an example? right now I have this. The bullet only spawns at the coordinates of the mouse (a kogel means a bullet).

I think all you need do is: Note that if your bullet moves too slow (less than maybe 5 pixels per move), the aiming will not be accurate -- maybe so inaccurate that it looks totally off. For the extreme example, if moving only 1 pixel per move, the movement will either be horizontal or vertical; no other angles will be possible unless you use a smooth moving engine (QActor or SmoothMover subclass of Actor). However, even moving at quite fast speeds, the aiming may be still slightly off without a smooth moving engine.