Has anyone rebarreled from 308 to Creedmoor? I'm having feeding problems with my Kimber. The heel of the shells sometimes is too low for the bolt to pick up out of the magazine and the shells sort of pivot on the shoulders making me think that the feed rails need to be opened up a bit.
The mag spring seems plenty strong and I have tried repositioning it. Also it fed fine when 308.

I've barreled many actions that were something else, to 6.5 CM, including long 700 actions, with out issue. Lots of 98 Mausers; those work fine as is.
It is the easiest conversion there is.
Bend your mag spring so it puts more pressure on the rear at the cartridge base. The lips on your mag box may need tweaking too; diagnosing feeding problems over the internet is impossible. In person, takes 3 seconds.

I'll give that a try. Also the action was cerakoted when it was rebarreled. Is is possible the cerakoting needs to be polished off of the rails? Didn't know if it might be less slick than the bare action.

Didn't your gunsmith check feeding? I always send the client a video of it feeding.
Unlikely but anything is possible with some of the work I see nowadays. Few real gunsmiths exist any more; parts replacers, they have all become. And assemblers of ARs, which is like tinker toys, not gunsmithing.
Post a picture of your follower on the spring; I already know how it will be angled.

I tweaked the spring to put more pressure on the rear of the shells and now it feeds.
Thanks Tom!

Good work!