Here is a great link explaining KB's: http://www.thegunzone.com/glock/glock-kb-faq.html I am asking because I had one in my G23 gen 4 and it really spooked me. When it happened, it blew the pistol out of my hands, blew out the magazine, and knocked the slide off the runners (but it stayed on the frame). Stung pretty good for a few minutes but I've still got all my fingers so no lasting harm done. Scared the crap out of me, though. I've shot several thousand rounds in the gun, almost all being factory reloads (BVAC, MBI, etc.). My KB happened while shooting BVAC 180 gr FMJ through a stock barrel. After much research, I am now shooting a KKM replacement barrel and have shot about 800 rounds through it with zero problems. Guess I trying to figure out how often this really happens, and circumstances, so would appreciate your data if this happened to you, I'd like to know ammo type, damage to you and/or gun, and barrel info of you'd not mind. Thanks!