I've had my Glock 23 for about a month now, and have been pulling my hair out trying to figure out why it sometimes fails to feed, regardless of what type of ammo I put in it. Turns out I only had myself to blame! Someone noticed I was having problems at the range and they instructed me to lock my wrists. Just like that, no more feeding problems. I know it is a newbie mistake, but I just wanted to out this out there for anyone else who might be experiencing the same issue. The crazy part is that I am in Security Forces and routinely shoot my M9 Beretta with no problems using the same grip. I guess the increased recoil on the Glock .40 needs a but more resistance to cycle the next round. I only hope this helps someone else who might be losing hope on their Glock.