I just bought a NIB Glock 23 Gen4. Love the everything about the gun BUT I am having an issue when i reinstall the slide on the frame. The slide will get to a point where its almost on but not quite and will not go any further. I am definitely not new Glocks I have had a 21sf,17 rtf2, and 26 and have had no problems what so ever with any those. Also I have a friend that just bought a NIB Glock 17 Gen4 that is having the same issue. Not sure if this something that anyone has experienced before or something that may go away with break in. I am able to get the slide on usually on the third try. Thanks for any advice.