Longbomber--from what I gathered in reading the posts, Mike was referring to Bosstom's gun being opened up from 243 to 270WSM in that post, not the OP's 7mm Mag. I don't have a dog in this fight, and don't know Mike from Adam, but your post is calling him out on something you misread.
I too am curious because I've been thinking about opening up a standard caliber to a magnum--namely a 5R .308 to 300WSM. Anyone else with experience on this subject, please chime in!
Tag for interest.