Steve, first off, where can an interested shooter read this? Esp. the chapter on chronographs. I do think that chronograghs serve a purpose but I also think that numbers as related to shooting are comparative but not absolute. Britt Jones and I have said that we were going to stack our chronys to see how close the results were, but we never have. In the example above, one would need a chrony to determine the SD. I do agree that the farther you do your load development the better because the longer distances would obviously bring in more variables.
As for the longer distances, I read once where this guy said that groups shot at 500 yards would need to be multiplied by 4(not 2) to guess a realistic size at 1000 yards. In other words, this would suggest a 2.00 inch group at 500 would be close to 8.00 inches at 1000 yards because of the added conditions. I suppose just shoot it at 1000 yards and find out for yourself. Thanks for this Steve and I hope others will state their experiences with this. WWE