Astral projection is not dangerous. It is as safe as sleeping.
Most dreams are probably unconscious astral projections, anyway.
Although there has been quite a bit written on the subject, astral projection is difficult for many people. The main difficulty is the tendency to forget dream consciousness upon awakening. Accordingly, the successful practice of astral projection requires work. However, the idea is very ancient. What sets it apart from a full OOBE is your hazy consciousness during the experience and poor recall afterwards.