Just a tidal shift. Back in the 2005-2008 the .243 was THE round to use. Then the Creedmoor came out and people started shifting back to the 6.5s including the .260, which was in limited use around 2003-2005 mostly by Terry Cross. Then the 6mm Creedmoor came out and did what the .243 did but with a little less powder in a better case design and people started going back to 6mm. It goes back and forth as they both work equally well. It comes down to the shooter.
What length barrel you have on that .260? I run 27-28" on my Creedmoor and it's easy to get that speed.