I was shooting a G27 and G31 today at the range, and I had the same malfunction in each that I don't recall seeing before. I suspect it was me since it happened in both with different magazines and ammo... The first time was with the G31...the slide locked back with rounds still in the magazine. Thinking I had bumped the slide stop, I tried releasing the slide to continue and the slide did not want to go forward. Then I tried removing the magazine, and it did not want to come out either. Finally, I tapped the magazine, and when I did this, the slide chambered the next round and all was normal and the slide locked back finally when finally empty. The second time it happened, it was exactly as described above, but with a G22 mag in the G27. I'm pretty sure the mags were firmly seated, and I also don't think I was riding the mag release. Does anyone know what may have caused this?