Quoted:
Just be aware that it is possible to jam the mag past the release and tie up the gun. I personally saw this happen at the shop I work at. It is imperative to install the grip spacers if you are going to stake your life on this gun. This will only happen when the slide is locked back. Still it is something to think about.
that's funny... because all of my glocks have a bit of material protruding in the magwell that interfaces with a flat relief cut in the magazine body (just to the left of the caliber marking on the back of the mag) to prevent that exact thing from ever happening. also, the ejector and the part of the trigger bar that hits the striker safety will prevent this from occurring as well...
But just to be open-minded... I just tried shoving a G17 mag way up in my G19... and it will only go about 1/16 of an inch past where it naturally sits... and it still stripped a round off and chambered it without an issue though I was pushing really hard on the bottom of the mag.
Where did you say you have "seen this happen" again??? Were you asleep??? HIGH maybe??? or worse... were you using KLINTON MAGS?!?!?!?!