Rocket, he asked for opinions, he's receiving opinions.
As far as I am concerned, Gail McMillan forgot more about barrels than most of us will ever know.
I own a DPMS LR308B. Same instructions came with it, shot it like I do every other rifle I own without following the time intensive break in procedure that DPMS recommends. You know what? It shoots just fine. So do my other rifles, be they semis or bolts.
As for the ones who follow this or similar procedure on every rifle they own, more power to them. Its their rifle and they can do whatever they like to them. When they claim it helps, I have to question, compared to what? If they break in every gun they own that way, what are they comparing it to? Someone else's? If that's the case, how are they accounting for the differences in each rifle or shooter ability?
But Gail put it best in one of his posts. A barrel manufacturer is in it for the business. Any competitive edge that gives his barrels a leg up on the competition he will employ. Gail found no advantage in doing nano coats, polishing rounds, or this break in procedure. As he put it, if there was an advantage in it, they would have done it from the factory from the get go.