Copied from me, from another thread:
My G19 had a stovepipe last weekend.
When I originally bought my G31, brand new in box, the mags weren't locking the slide on the last shot, and even weren't loading the next round a few times. Took it back to where I bought it and they put stiffer mag springs in... same problem. They still weren't working. Took it back again and they gave me two new G22 mags. So far so good with those, but I rarely shoot the thing because of the cost of 357sig ammo so who knows really.
Odd enough, for all the praises Glock gets for being so reliable and built to survive anything, of my seven pistols bigger than 22, the only two I have EVER experienced any sort of malfunctions/ failures with are my two Glocks. Berettas - flawless; HK - flawless; Steyr - flawless; XD - flawless. All of those mentioned have 1k rounds or more.
Oh well, I ain't bitchin'. I still love my Glocks and would take them anywhere.