Last week I experienced something that I had never seen before. I had a partial head separation with a brass case (sorry, no photo). My KelTec PF-9 jammed with a FTE and the extractor was partially disengaged from the slide. I checked the case and found a crack at the web that went through the case at the extractor cutout. It was cracked about 3/4 the way around the web on the inside. It almost looked like the head was ready to come off. It kinda looked like it was a 2 piece design that had come loose. This was not a blow out above the web at the place where you normally see a bulge on my G17 fired brass. This was at the bottom of the head. When I looked inside the case it looked like the junction between the case sidewall and the bottom of the case was a 90 degree junction with no internal taper. The load was mild. It was 4.8gr Unique and a 124gr. Berrys. Any thoughts?