The retrieved case looked as if it contained a full charge of powder, it was right up to the neck. The top section of the powder looked normal, bright shiny beads - but the powder did not fall out of the case when turned upside down. It had loosely clumped together. When eased out, using a toothpick and jeweller's screwdriver, most of it appeared unburnt but there were small clumps of charcoal like material.
I don't know whether this is indicative of the powder and/or primer being defective. Maybe the amount of primer was insufficient to trigger normal powder combustion and/or maybe the powder was contaminated. Also, there was a hairline crack in the case neck and many of the cases had speckled staining.
However, I do know that the sound of the gun as it was fired was normal and that if Section 2 of the article on HM2 testing also applies to the HMR it could explain a lot of blow ups as being attribtable to obstructed barrels.
http://www.eabco.com/17HM2Testing.htm
