I am wondering how secure the rear sights are on Glocks. I have an issue with the way the right armrest of my work chair catches the back end of my G27 slide every time I stand up. I've actually been thinking about manufacturing a kind of shield to attach to my chair to minimize this. Anyways, since the rear sights are just essentially wedged into the slot, has anyone here had an experience of having them knocked out of true by getting it snagged on something? They haven't moved yet but it only takes once to ruin my day. And for the record, I'd rather change my chair before I change my EDC, heh.