I'm hoping on some comments from some knowledgeable gun owners. I just purchased a colt delta elite 10mm. Have not fired it yet and noticed one of the magazines that come with it does not lock the slide back when I rack it with an empty magazine. I tried the second magazine and when I racked the slide with the empty magazine the slide locked back properly. I called colt and they told me to send them the defective magazine and they will send me a new one. My question is do you think it's just a bad magazine or is it the gun? When comparing the two magazines I did not see anything that differed from the two. Should I be worried?