Type 1 has a problem in that the plunger (or slug) is not within the main magnetic field so the pull force is relatively low. The nearer the slug gets to the coil armature the greater the force experienced
Type 2 plunger is the armature and is contained within the magnetic field so the pull action is much higher. The plunger will attempt to "balance" itself to the centre of the magnetic field. Providing the plunger is longer than the coil you can get it to extend beyond the coil end.
Wikipedia "reluctance" and google "magnetic circuit" for all you could ever want to know.