Can you close the bolt on an empty piece of .30-40 brass?

Head spacing may not be the issue as much as circumference tolerances also.

If you cannot close the bolt with no round loaded, that raises lots of issues as to what changes were made in the chamber of this rifle. Was it damaged when worked on? Does it visually look clear in the chamber area? Since a different bolt won't work either, the gunsmith who worked on it must have damaged it somewhere. Does the bolt close a little but won't turn fully closed as if the rear of the new barrel is set back too far?

Close ups of the chamber would help. Hard to figure out without it in hand to manipulate.

The gunsmith certainly should have checked his work after changing barrels. If it won't work, you need to send it back!