if you rebarrel, the 280 is as simple as running a 280 reamer in a 7mm barrel blank when they chamber it... same parent cartridge as the 270 so the rim is the same diameter and the bolt face will not need to be modified... the magazine will work just fine with the 280 round also...

local gunsmiths here rebarrel for 500 - 550 by the time they disassemble, buy the blank, chamber, thread, cut and crown it, assemble it and blue it...

don't rule out douglas barrels either. I have a Shilen and a Douglas and both are quality barrels.. the Douglas is actually better than the Shilen as far as copper fouling but then again the Douglas is hand lapped...