OP, I am a .260 fanatic, I believe it to be an excellent round. I preferred it over the Creedmoor due to the brass availability. I've taken a liking to necking up Winchester .243 brass.
However, I am now having a rifle chambered in Creedmoor because I am very familiar with the 6.5 ballistics (know much of my elevation and light winds off the top of my head out to 1k) and really like the 6.5x47 Lapua round also. Anyhow, I wanted the option to be able to use factory ammo if I was feeling too lazy to load, but Lapua now offers the small rifle primer pocket, so I have a 28" Creedmoor due to me at the end of this month.
ETA - yes, your bolt and mags should work between the Creedmoor and .260. I would be recalcitrant to run any ammo loaded with that Lapua small rifle primer brass if you don't have a small firing pin hole. That's a lot of pressure to not be fully supported if you used the large FP hole and those cases.