I had something happen yesterday at the range that I thought needed to be shared. I had a quantity of 9 mm reloads; 4.9 grains of Power Pistol behind a 124 grain Acme coated "lipstick" RN bullet. I've used literally thousands of this load with no issues whatsoever. The reload brass are various range headstamps, and again, never had an issue before- I generally pick up more at my range than I shoot. I've noticed that some of the brass I get- either at the range, or before I joined this range, purchased range brass- has a "step" in it (photos attached-the ones of the cases sawn in half courtesy of my brother, mongoose33 ). Also attached are photos of what happened to the case I referenced; it split AT THE STEP into two pieces of brass. I keep an eye on case condition when I sort it from the range; I pull all the NATO brass, because I don't want to deal with the crimp in the primer pocket and I get enough that I'm not concerned about the NATO brass. I have also measured the 'step' brass case volume; it lies well within standard variance for different brass headstamps, so I wasn't concerned about that, either. So, not only do I inspect when I pick it up, but also when I deprime, when I tumble them with the stainless pins, when I lay them out on cookie sheet/towels to dry in the oven, and when I count them into containers of 500. Never noticed anything wrong externally, or I would have pitched it. My theory is that the 'step' creates a stress point that flexes, and after several reloads, the case is weakened enough at the'step' that it just splits under pressure. The bottom of the case ejected normally, leaving the top in the chamber, and the next cartridge naturally wouldn't chamber; jammed with the slide partly open, and when I ejected it,
came out with the top of the step case around the bullet of the next cartridge.
Long story short, I am sorting through ALL of my 9mm brass and pitching all of the 'step' brass. The case that split was *IMT*, but there are several other brands that use that same configuration, and I'm pitching them all.
Just got done sorting 3000 cases. Headstamps found with the step are: IMT and *IMT*; the asterisk is the closest I can come to the symbol, looks something like a stylized globe. AMMOLOAD and FM are the other two I found; at least for me, quantities ran around 2-3%; I found some 68 in 3000.
came out with the top of the step case around the bullet of the next cartridge.
Long story short, I am sorting through ALL of my 9mm brass and pitching all of the 'step' brass. The case that split was *IMT*, but there are several other brands that use that same configuration, and I'm pitching them all.
Just got done sorting 3000 cases. Headstamps found with the step are: IMT and *IMT*; the asterisk is the closest I can come to the symbol, looks something like a stylized globe. AMMOLOAD and FM are the other two I found; at least for me, quantities ran around 2-3%; I found some 68 in 3000.
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