After having my kc02 for about six months, I am starting to notice an issue with my magazines. The port on the magazines where the gas is fed into the bolt through is chipped in the same place on all of my magazines. It is on the back edge of the plastic piece that the gas escapes from when you fire the rifle. From the way it chipped it looks as if the bolt or bolt carrier is striking it, eventually weakening the plastic enough to chip. Has this happened to anyone else?