Yes I reach the same state in my meditations. It's when you're completely open and relaxed. Your mind has reached a point of silence that is up there with the sleep realms. It definitely is a form of astral projection.

I was in it so deep once my whole body seized up and I left my body and it was a really scary but rushing euphoric feeling I don't know what made me scared about it, it was just unexpected and sudden. You can then travel to places and they seem very real. I think it is a DMT release in the brain as well as the places you visit in your head seem very real