I have heard from quite a few people that keeping the magazine full of bullets (I own a XD-9 4 inch, so that would be 15 bullets) is bad for the magazine. People ahve said that you should only keep 10 bullets in there, so that the spring does not become worn too badly. To what extent is this rumor/myth/fact true? Any feedback would be appreciated. Also, I pointed out that police officers leave their mag's full, of course... so is it bad to do so? I heard it may jam the feed if the mag is full too long and the spring does not have it's original strength.