Re: Question about SD, ES, and accuracy
I recently was developing a a load for a new 300WM intended for LR hunting. I optimized two loads, same components except different powders, H1000 and Retumbo. Due to the powder shortage I really wanted to use the H1000 and conserve my lot of Retumbo for my 6.5x284. Accuracy testing at 100-300 yards showed the group size of H1000 was suoerb with consistent groups in the .25MOA range. The Retumbo was running .5MOA average. I was pretty happy with H1000 until I got to my chronographing. Chrono testing of both loads on three separate days, using my Magnetsoeed and Oehler gave consistent readings of 2825FPS with an ES of 25-35FPS for the H1000 and 2902FPS with an ES of 8-12FPS for the Retumbo. While the H1000 clearly seemed to produce the best accuracy at shorter ranges, it did produce vertical stringing at 1000 yards about 12-15" in size. At 1000 yards the Retumbo maintained symmetrical groups that were very close to .5MOA, vertical stringing being half the H1000. Except for my bullet, 210 Hunting VLD, I tried adjusting the variables to bring the H1000 down in ES, but couldn't get there. Ended up settling on Retumbo. I think this is the kind of situation where a chronograph proves to be very useful.
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