I bought a new M&P 40 last weekend and really like the feel and looks of this pistol but haven't had a chance to shoot it yet...I loaded both 15 round magazines (which about wore out my thumb)..I have never had a double stack magazine pistol before but after loading both mags and giving them a good whack on the back to seat the bullets they rattle inside the mag...I removed 1 round down to 14 and again whacked the mags several times and the rattling would stop for a while but then come back which makes the gun sound like a metal bucket full of nuts and bolts...My question to you folks, is this normal and is there a way to prevent it? In all my other single stack 1911's and my 4506 the bullets are held firmly by the mag spring and don't rattle at all...Other than this annoying problem I like everything else about the pistol and it seems to have a nice trigger pull and sight picture...Any thoughts on the rattling would be appreciated...As always, thank you all....