That certainly looks way too light for using AA#9 to me, especially based on my experience with Pearce's loads. I don't doubt that failure to achieve proper burn characteristics and pressure was the likely result. Even with a magnum primer and crusher crimp it may have issues. This must have been holding to a 14Kpsi level load. I don't know of any AA#9 loads at that pressure level; most load data shows it more suited to pressures above that. E.g., it is a great heavy bullet 10mm and Blackhawk level 45 Colt powder!

edit/ Just checked the new Accurate manual and they do list loads in 45 Colt as low as 17.5Kpsi. Interesting. I usually like it to be above 20K at least before I consider using it.

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