What is the benefit to knocking the mag release lever with the full mag when doing non-retention mag changes with an ak style rifle? Seems just as easy and effective to do it with your thumb and you don't have to re-orient the new mag to insert it once the old one is out. Almost every tutorial I find shows it done this way. Is there a valid reason, or is it just the way it's always been done so people figure it must be right?