Originally Posted by CWPINST
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.
Could have been most anything...over-worked or just bad piece of brass, overpressure due to bullet setback, overcharge slipped through, etc., etc. From the extreme low location of the separation I'd tend to think the brass just developed a crack that probably was'nt visible externally. I wouldn't sweat it too much if you know your loading technique is good, Winchester brass is historically very good. That said, unless you fired it when new with the NATO brass, it's true load history may be suspect (some sold as "once-fired", ain't).