I think the ‘destroy outside the screen’ behaviour just deletes an object when that object passes outside of the currently shown camera area. You don’t set the area yourself in the event.
If you want to destroy the bullets after they have moved a set distance then you can just delete them after a certain amount of time as this will correspond to a particular distance (based on the speed of the bullet). A bullet moving at 100pixels/sec will be limited to moving 100 pixels, if it is set up to be destroyed 1 second after it was created.
Example here: