I just bought a used Kimber Montana. It shoots good, but I noticed that the bolt rattles. When it's closed on an empty chamber, you can move it forward and rearward at least ..005" or more. All bolt guns I've held have been tight. Is this normal? Or is it safe? I mean we're getting into headspace here. Why would Kimber not catch this?

It’s not a headspace problem unless it rattles like that with a round in the chamber.

Safety on or off?

Shouldn't do that off.

With the firing pin released it’ll be loose and free to move fore-aft until either the handle hits the action or the extractor, bolt hits the counterbore or cone. Should be more than .005”, and not related to headspace.

Cocked with the safety on. Of course it's tight with the safety off.

Also a factory round in the chamber stops all movement, but that's expected. I've owned and held many brands of bolt actions and have never seen this. Some were tighter than others, but never any movement or rattles