ntsqd
Well-Known Member
I've been searching here and have found quite a bit on the topic, but most of those threads are at least a couple years old if not older. I'm curious if this is considered "put to bed" or recent experience has lead to revisions of thought.
I see there's a school of thought that says measure case volume, case weight is useless.
And I see the school of thought that says case weight is a reasonable indicator of case volume.
My own thinking, right or wrong, is that if you filled the chamber with melted-down case brass, trimmed to case length, and weighed that, then weighed a case fired in that chamber that, less the elastic return of the fired case, the difference in weights is the case volume. This assumes that the brass density is the same. I would assume that they are not the exact same density, but that the delta is small enough that in the volumes under consideration that statistically it is noise.
So my conclusion is that weighing cases is an indirect measure of case volume that within mfg lots is consistent enough for our sorting purposes, but that considering weights of different mfg's cases or even cases of the same mfg, but from different lots is an error.
The question that lead to this search is: What tolerance is allowable for "like" weight cases? 0%? 1%? 10%? i.e. with cases in the ~116 grain weight range (.224 Valkyrie) what is an acceptable sorting increment? Sort by 1.0 grains? Sort by 0.1 grains? Sort by 0.01 grains?
I see there's a school of thought that says measure case volume, case weight is useless.
And I see the school of thought that says case weight is a reasonable indicator of case volume.
My own thinking, right or wrong, is that if you filled the chamber with melted-down case brass, trimmed to case length, and weighed that, then weighed a case fired in that chamber that, less the elastic return of the fired case, the difference in weights is the case volume. This assumes that the brass density is the same. I would assume that they are not the exact same density, but that the delta is small enough that in the volumes under consideration that statistically it is noise.
So my conclusion is that weighing cases is an indirect measure of case volume that within mfg lots is consistent enough for our sorting purposes, but that considering weights of different mfg's cases or even cases of the same mfg, but from different lots is an error.
The question that lead to this search is: What tolerance is allowable for "like" weight cases? 0%? 1%? 10%? i.e. with cases in the ~116 grain weight range (.224 Valkyrie) what is an acceptable sorting increment? Sort by 1.0 grains? Sort by 0.1 grains? Sort by 0.01 grains?
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