Buddy of mine is a gunsmith and he recently reamed out a factory 6.5 creed Tikka to a 6.5-280 using a custom Manson reamer he spec'd out. Don't know the particulars of the reamer specs but he did text me some initial load data, since he knows I like that stuff.
6.5-280, using Nosler .280 AI brass necked down. He's only tried one bullet and powder combo so far.
N560 under a Nosler 129 ABLR, 23.5" barrel suppressed:
61.0 gr - 3141 fps
61.5 gr - 3176
62.0 gr - 3269 pressure signs, likely max
62.5 gr - 3243 over max
63.0 gr - 3302 blown primer