I've been running the Garmin since it first came out, having run in succession Shooting Chrony, Pro Chrono Digital, Magnetospeed V3, and Labradar over the years. The Garmin has been a quantum leap in my opinion. However, I ran into something this week that I just can't make sense of...
I had hit the end of an 8# jug of Retumbo, and opened a new one from a different Lot #. When I went to the range, I ran 10 rounds over the Garmin (300PRC) - the first two rounds were the last from the old lot of Retumbo, the other eight were from the new lot. The first two rounds were right on track with my established AVG MV for the load. However, when I got to the next eight rounds from the new lot, the MV jumped up about 20fps on average. More than I was expecting, but I get it - the new lot is hotter than the old. The ES for ALL 10 was 38, and the SD 12.8. Since the last eight rounds from the new lot were considerably faster than the first two from the old lot, I wanted to find out what the numbers were for just the new lot, so I deleted the first two shots and checked the Session Summary. My ES went way down from 38 to 24. BUT, my SD jumped up from 12.8 to 15.3. The new ES is correct, but I can't see any way the SD could go UP, especially to 15.3 with only a 24 ES. I've never seen such a high SD-to-ES ratio.
I had this happen once before fairly recently, when I deleted a couple rounds from a string that were suspect due to some inconsistencies that had happened during the reloading process. The suspect rounds were marked prior to firing. When I deleted them from the Session, the ES went down and the SD went up. I thought it was a bit strange at the time, but shrugged it off as just the way the velocities distributed themselves. It wasn't anywhere as dramatic of a shift as this last incident was, though. This time I was sure there was a problem in the way the unit re-calculated the SD.
In the past, if I ever deleted any isolated extreme high or low shots (out of curiosity), the SD would come down along with the ES. However, there was a fairly recent software update pushed, and both of the incidents related above have occurred since that update was installed.
Anyone have any insight?
I had hit the end of an 8# jug of Retumbo, and opened a new one from a different Lot #. When I went to the range, I ran 10 rounds over the Garmin (300PRC) - the first two rounds were the last from the old lot of Retumbo, the other eight were from the new lot. The first two rounds were right on track with my established AVG MV for the load. However, when I got to the next eight rounds from the new lot, the MV jumped up about 20fps on average. More than I was expecting, but I get it - the new lot is hotter than the old. The ES for ALL 10 was 38, and the SD 12.8. Since the last eight rounds from the new lot were considerably faster than the first two from the old lot, I wanted to find out what the numbers were for just the new lot, so I deleted the first two shots and checked the Session Summary. My ES went way down from 38 to 24. BUT, my SD jumped up from 12.8 to 15.3. The new ES is correct, but I can't see any way the SD could go UP, especially to 15.3 with only a 24 ES. I've never seen such a high SD-to-ES ratio.
I had this happen once before fairly recently, when I deleted a couple rounds from a string that were suspect due to some inconsistencies that had happened during the reloading process. The suspect rounds were marked prior to firing. When I deleted them from the Session, the ES went down and the SD went up. I thought it was a bit strange at the time, but shrugged it off as just the way the velocities distributed themselves. It wasn't anywhere as dramatic of a shift as this last incident was, though. This time I was sure there was a problem in the way the unit re-calculated the SD.
In the past, if I ever deleted any isolated extreme high or low shots (out of curiosity), the SD would come down along with the ES. However, there was a fairly recent software update pushed, and both of the incidents related above have occurred since that update was installed.
Anyone have any insight?
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