Originally Posted by dm1906
Good habits is the best laboratory. Never assume what you get is the same as what you had, even within the same name brands. In my case with this incident, had it been a full-on KB!, it wouldn't have been much more, if any, eventful. More alarming, perhaps, but not necessarily more eventful or dangerous. New loads get the full treatment. Spectra gloves, eye and face protection (ballistic hearing and eye protection is standard, in any case, all the time), and no mag. When a case fails on these, it will blow out the bottom (unsupported or least support at the ramp). With a mag in place, cartridges or not, the gasses build until something gives. This is usually the mag latch, mag, followed by the sides of the frame. An empty grip gives the gasses a path to exit quickly, almost always enough to prevent a pressure build, and pistol damage. Revolvers and single shots aren't so forgiving. They just blow apart. Ideally, we should be testing with a machine rest. I've never had one (although it's been on my list for 20+ years).
I've seen this happen a few times over the years. Most of them were new common name brands. The first was .41 mag, which resulted in separated case heads on Federal factory rounds. My Model 57 handled it fine, and has been fine since, after several thousand rounds. It did make a trip to S&W for inspection after that, though. The next was a bunch of "Eastern Block" 7.62x39 new brass. One crack and two blow-outs and I tossed the hole lot of 2500 (after disassembling 500+ rounds....not fun).