Had this happen today and I thought it was interesting enough to share. I was shooting my 9mm 1911 and on this round I felt a bunch of particles hit my face and lighter than normal recoil. The case was still in the extractor and jammed between the slide and the rear face of the barrel. No damage to the gun or anything else. I believe it was a defective case but maybe something caused an overpressure. Was loaded on a progressive press with a powder lockout so an overcharge is unlikely. I believe it was just a defective case.