This from the person who so fervently extolled the virtues of what did you call it..... OCW

Accuracy loads are not always tested by shooting a loaded cartridge downrange, many are shot in a pressure barrel and the load listed produced the most consistant pressures. Take it with a grain of salt, I have had accuracy loads from both Nosler and Sierra that have produced excellent accuracy and others that have not faired so well. I ideally try to go for a load density greater that 80% but that does not always produce the best groups. I decide on bullet then start with the bullet manufacturers data unless I can't get acceptable accuracy then I go to the powder manufacturers data. That being said I also like to use the Lyman manual as an unbias data source for reference.