Originally Posted by 243yote
So i finally took chrono to the range to see what my loads would do. Finally just used old spotting scope tripod to mount chrono on. It works great! Now my question to you more experienced loaders. How do i interpret the chrono info? SD,ES,Avg? My best groups had the lowest numbers. I worked up a new load with new powder. Tried some old loads just to see what i was getting also. Old loads were just a bit faster.
SD, standard deviation, is a statistical measure of uniformity of your shot string. ( to much math to mess with)
ES, Extreme spread of your shot string, high and low velocity spread.
shot#1 3000 fps
shot#2 3015 fps
shot#3 3030 fps
ES = 30 fps
AVG, average velocity of your shots in your shot string.
example; AVG, 3015 fps
Look to workup a load that keeps your ES as low as possible and that should be your most accurate load as long as you do your part shooting. I try to get my ES in the low teens and thats good enough for me. slower loads are the most accurate alot of the time but I look for powders that give as close to 100% case density as I can get and play with it from there.