Went shooting a couple of weeks ago, haven't had a chance to deal with this after the outing until now... I was out with my G23 (.40) and another non-Glock (ewwww) handgun. I had four new factory magazines with me for the G23 that I was testing out (as if they wouldn't work right out of the box...) Anyways, there were absolutely no problems, hickups, jams, FTF, or anything of the sort from the Glock. Thus far, completely normal (that G23 has NEVER given me any trouble). This Glock is about 18 or 20 months old, I bought it new in the summer of '08. I think I've got between 3000 and 4000 rounds through it. At the range, I never disassembled it or anything. I just took it out of my holster, shot the mag full of JHP, then started loading it with FMJ. I think I put 150 rounds through it that day. When we got home, I disassembled it for cleaning, and this very small piece of metal fell out. We couldn't find at first where it came from, but my friend has a glock also, so we held the lowers side-by-side until we found the difference. There are two small, rectangular pieces of metal on the inner lip of each rail just below where the receiving end of the barrel sits. I can't seem to figure out what these pieces are for... It does not disrupt the railing configuration - the slide still fits on perfectly and the gun functions like normal when I fire it with snap caps. Could they be simply reinforcement? And what would happen if I fed it live ammo? I have been carrying around my Kahr CW9 ever since! I feel naked without my Glock! Because of it's age, it is just outside the warranty period of 1 year. Please help!