It begs to ask if you checked the rail mounting screws to ascertain if they are proud of the inner diameter of the chamber. Easy to check, pull the bolt out entirely and take a bright flashlight and illuminate the interior of the chamber, paying close attention to the upper area below the rail. The mount screws should not protrude below the inner surface of the chamber at all. If they do, they will interfere with the bolt movement. Also, check the bolt surface for scratches, a sure sign of proud rail mounting screws.
Possibly you do have an undersized chamber. Glad I don't on my 11 LRH.
All my Savage bolt actions exhibit a stiff bolt withdrawl or at least stiffer than other bolt rifles I have.
Personally, I don't care for Black Hills ammunition, at least in .223. They are loaded hotter than all get out.