I am very soured on McMillan stocks, but...
Last decent stock I got of theirs was an Edge for Rem 700LA. Bought in 00/01. Some years later I opened it up a bit on the barrel channel and stuck a Sendero SF barreled action in there. The barrel was timed just right so that the flutes hung just over the sidewalls of the stock.
That was a nice rifle. Never a problem with that stock.
Sendero SF in magnum caliber (.300 win mag). Barrel is a light varmint contour, but that means different things to different barrelmakers.
Good luck with any McMillan inlet for barrel channel. If your gunsmith has decent stock inlet skills, talk to him/her about getting a blank from McM and going from there. No hassles that way...
