Wasn't it later stated that the Varget tests in the 223 were before he started the barrel cooling/ammo cooling phase of his experiments?
He mentions that in this article here:
http://www.shootingsoftware.com/ftp/Pressure%20Factors.pdfHowever as this paper also shows, which does control powder and barrel temp; the end result is that it is application specific.
Also confirmed here, FAQ#7
http://www.accuratepowder.com/faq/