I recently sorted 300 Lapua .308 Winchester cases to use with a new barrel. All were the same lot and sorted on my Acculab VIC 123. I am accustomed to seeing a fairly normal distribution about the mean, perhaps with a little skewing. The attached histogram represents the distribution that I obtained. Note the two, distinct distributions and the relatively large spread, from 171.00 to 173.30. It was still good enough to provide several groups below the .25% threshold that I have found necessary. These cases are for long-range shooting and short-range benchresters have much more stringent standards.
If the sample population was larger, we could reasonably expect to see a return to expected results. It is possible that there was a problem with this lot that still fell within Lapua's acceptance criteria but resulted in the depicted distribution.
I posted this to emphasize the importance of weight-sorting for best and most consistent accuracy. Even when using excellent brass like Lapua, manufacturing variances occur.
If the sample population was larger, we could reasonably expect to see a return to expected results. It is possible that there was a problem with this lot that still fell within Lapua's acceptance criteria but resulted in the depicted distribution.
I posted this to emphasize the importance of weight-sorting for best and most consistent accuracy. Even when using excellent brass like Lapua, manufacturing variances occur.
