I'm sure this isn't the first time this has happened, but I had a friend at my house today with his new Glock, and he accidentally removed the slide with the mag in place. There was no ammo in the room so he learned a safety lesson, but he realized his error when he couldn't get the slide back in place on the frame. I had told him prior to reassembling it to do it carefully and with ease so he never forced it when he met resistance so I don't think he damaged anything (except his pride), but I told him I would ask the experts on here. I looked it over pretty well and everything looked good to me, and it worked fine with cycling dummy rounds. Thanks in advance.