Jeff, make no mistake about it, McMillan does the best possible job of bedding their own stocks. Their pillar-bedding is the absolute best to be had, and many custom riflemakers who employ McMillan stocks actually have McMillan do the installation, including the bedding and painting.
The first McMillan stocked & bedded rifle I ever owned was my old .300 Win. Mag. that was built for me by Glen Pearce. Glen did all the metalwork, etc., but McMillan installed and bedded the stock with machined aluminum pillars, installed the pad and swivel studs and did the painting. I'll never forget the first time I took that rifle apart and examined the bedding. It was absolutely perfect, with no binding anywhere. When you tightened the screws, they were TIGHT and stayed that way. And that rifle NEVER changed point-of-imapct in all the time I used it.
I've owned several such rifles since, and every single one of them was just as good as that first .300 Winchester.
I consider it counter-productive and an act of false-economy to order a McMillan stock and not have it installed by McMillan..........