I have a chronograph, and it works very well, but the only time I use it is when I'm making a drop chart on exbal. I still do it the old fashion way leg work, and shooting. I pick my best groups, and that's what I go with, and it seems to work fine. I don't care what the ES or SD number is as long as it shoots well! Now for the question. Could a person just shoot through a chronograph at no target, pick out the best ES and SD, and that be his load? Does a low ES and SD number mean that it will shoot good? Can a high ES and SD number out shoot a low number? Just curious. Thanks for reading.