I've carried the same Glock 17 since 1988 and have owned countless other Glocks and have sworn by them since the beginning. However, about a month ago, I removed the mag from my g17 and discovered there was a crack in the plastic running down the back of the mag (non drop free factory mag that came with the pistol in 88). So, I load the spare mag that also came originally with the pistol. On a recent road trip, I'm talking to a friend and remove the mag to do a show and tell of where the other mag was cracked and to my surprise, this mag is also cracked down the back worse than the other. Let me say that I maintain my weapons quite well and the pistol nor mags have ever been abused. In fact, the mag was/is loaded with 15 rds ammo rather than 17. I've seen all metal mags develop stress cracks but only after extensive use. I'm going to send both mags to Glock to see what they will do about it. Hopefully, they will replace them at no charge but the fact that they basically self desinigrated is a concern. Anyone else had this happen?