7STW to .280? Can this be done and why/not????

[Mills]

This is probably a dumb question, but I'm going to ask it anyway. Can a gunsmith take a 7mm STW action and somehow modify it into a .280? I realize the bolt face of an STW is .531 and the bolt face for a .280 is smaller at .473, but could a new bolt be used in the original action? Would there be problems with the .280 cases in the magazine? You see, I own a Sako 75 7STW, and want to get away from the magnum cartridge. Would love to modify and twist on a new barrel if possible.
Again, sorry if this is a really dumb question, but like I tell my kids, I'll never know the answer unless I ask.
Mills