kB's
I saw my first Glock kB this weekend. The kB occurred using factory ammo in a G21 (.45). In retrospect, perhaps we should have seen it coming.
I was at Front Sight in Nevada, taking their 4 day defensive handgun course (which I highly recommend, btw. I was very impressed.) One of my fellow students was shooting American Ammo through his G21. I was on the line next to him on several occasions and noticed he was having some jacket separation issues. After close-range shots there would be one nice, round hole, and several smaller shrapnel-type holes. On the fourth and final day of the class, we were doing timed presentation and firing drills from various distances. Since we were all firing in the same very short time limits, I didn't even hear it blow, though the shooter was only 2 students down the line. I was conducting my after action drills when I noticed the gun on the ground and the student hurrying back to the back of the range. I reholstered my own pistol and noticed my hands were wet. I looked down and saw I had blood on my shirt and hands. I had caught a small piece of shrapnel of some sort in my finger.
Inspecting the G21 after the kB revealed classic kB effect. The mag was blown out the bottom, and the mag floor and spring had been blown out of the mag. The mag floor ended up approximately 15 feet to the shooter's left. The sides of the grip just below the chamber were blown out and the slide was bowed outward. The round was still partially in the chamber and was cracked and seperated in the 6 o'clock position, where the cartridge was unsupported.
The ammo was labeled American Ammuntion, "copper coated." I didn't write it down, but if memory serves they were 230 grains.
I don't know if the student had cleaned his gun over the course of the 4 day class. The good news is that he while he suffered a fairly severe cut on his hand between the thumb and index finger, and some powder stippling on his face, there did not appear to be any permanent damage. After having the cut bandaged by the on-site EMT's, the student returned to the range to finish the course with his Kimber.
I don't know the actual cause of the kB, and the parts of the gun were retrieved for later analysis, but I suspect that the seperation of the copper coating "jacket" allowed lead deposits to accumulate in the polygonal barrel. The student had fired approximately 700 rounds of this ammo over the 4 day course, and if he didn't clean the gun it might have allowed lead build-up.
I am still considering purchase of a G21, but this gives me pause. I would recommend in any case to avoid the particular combination of copper-coated ammo (rather than jacketed) and extended firing of the Glock.
I hope that this may save another person's hand who might otherwise have thought that kB's "don't happen with factory ammo."
addendum: I forgot to mention that, ironically, the student had previously ordered a Bar-Sto fully-supported-chamber barrel for the G21 that kB'd, but it didn't arrive in time for the class.
