Not sure how long ago it was, but formerly velocities in the US were quoted over 40 yards. The beginnings of these velocities over a longer range have their roots in when measurements were taken with a "Boulenge Chronograph". These instruments simply were not capable of measuring small enough time intervals to give accurate readings with close screen spacings near the muzzle. These often had the start wire attached to the muzzle itself, but the stop screen some distance down range. For shotshell velocities the 20-40 yard range was about the near & far limits of their range. Modern Chronographs capable of reading very short time intervals changed all this. The former though did prove to be quite accurate when used within its capabilities.
