If you really believe the information you've presented in your post above is sufficent to conclude that the bullet manufacturer's data are "off," do yourself a favor and run it by some guys who do this kind of testing for a living. Cut and paste your post into the gunwriter's forum and ask Mule Deer if your data are good enough to conclude that the bullet manufacturer's data are off.
Be sure and mention that it's one day of testing, and be sure and mention the make and model of your chronograph.
Hell's bells, you don't even know what barrel length the manufacturer used.
