See this in the S+B cases. Honestly though, what I thought was more interesting was that nasty crater on the primer, got a better pic of that? I *think* what this case is trying to do is compensate for a lack of powder with over pressurization. The compacted load might build up a higher PSI value than a stiffer load that has more give to it, perhaps because the weight of the extra space in brass is more expensive than the reciprocal weight in powder. At least, that makes sense in my head.