Hey guys, I have a quick question. One of my magazines won't lock back on the last shot. Even when I rack the slide when the magazine is empty, it won't lock the slide unless I do a really hard and long pull. Do you guys have the same problem? During my first range day, all 3 did that until I went 100 rounds through the gun. Now the gun has 400 rds on it and only 1 magazine has been doing it. Should the mag be broken into?