Again, thanks for the data. It should be the only thing that makes us change what we do, not old wives tails, rumors, or stories from guys with more gray hair than we have. I took some graduate level courses in statistics, and now it is all done by computer, so easy to calculate (but I worked all night most of the weekend, and was too fried to try). Basically, the questions are: is the data normally distributed, and is there a statistically significant difference between the groups.
The next experiment should be to see if the SD increases with multiple loadings, or, as the primer pocket gets dirtier, does the consistency decrease? You said you did not clean the pockets, but did you use the ultrasonic cleaning technique (clean and shiny), or were the cases simply resized and prepped as they came out of the gun? If the former, the US technique by itself does a fair amount of cleaning compared to uncleaned brass, or brass just run through a vibratory media.
I have been struggling to get max accuracy out of my 223 AR, including primer pocket uniforming, neck turning, chamfering, controlling neck tension, etc. However, it seems that the AR platform is so rough on brass that none of these things will do much good, and that largely bullet choice followed by powder choice and load are the only real factors.
However, the only way to make logical changes is through the analysis of data, and this is what you provided, so thanks.
The next experiment should be to see if the SD increases with multiple loadings, or, as the primer pocket gets dirtier, does the consistency decrease? You said you did not clean the pockets, but did you use the ultrasonic cleaning technique (clean and shiny), or were the cases simply resized and prepped as they came out of the gun? If the former, the US technique by itself does a fair amount of cleaning compared to uncleaned brass, or brass just run through a vibratory media.
I have been struggling to get max accuracy out of my 223 AR, including primer pocket uniforming, neck turning, chamfering, controlling neck tension, etc. However, it seems that the AR platform is so rough on brass that none of these things will do much good, and that largely bullet choice followed by powder choice and load are the only real factors.
However, the only way to make logical changes is through the analysis of data, and this is what you provided, so thanks.