March 21, 2011, 04:38 PM
What's the significance of weighing cases in reloading? Is this an accuracy or a safety issue?
March 21, 2011, 04:42 PM
1. Comparing case capacity with two different brands of brass.
2. Segregating cases into lots that weigh the same for potentially better accuracy.
There is no "safety" related reason to weigh brass that I know of, other then #1 above when comparing case capacity of different brands of cases.
March 21, 2011, 04:50 PM
It can potentially affect both of those. The presumption is that 2 pieces of brass have the same exterior dimensions. If one of them weighs more, then we ASSUME that it is due to the brass being slightly thicker. That would tend to decrease the interior volume. That would mean 2 things. First of all, the heavier case would have less room for a maximum powder load. More importantly though, the interior volume is less, so the pressure developed when firing will be higher when compared to a case with a larger volume. If you were dealing with pressures already approaching maximum, then a slight increase in pressure would be very bad. But even if you are dealing with the mid level pressures, then any increase or decrease in pressure could affect the velocity and accuracy.
There are a lot of assumptions involved there. For benchrest shooters, it is worth measuring and sorting according to weight. For most average shooters, it might not be worth it unless you just enjoy that kind of attention to detail. When I compare 2 diffeent brands of brass, I have seen enormous differences in brass weight, as much as 15-20 gr. Using the same bag of brand brass though, I usually see them fall within a 3 grain window. By my standards then, it's good enough to sort them by brand name. Maybe sample a few to make sure they are reasonably close, but that's good enough for me.
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